No kingdom is an island unto itself, and in Ravenloft, the Vistani provide an important function often overlooked by many DM's.  Introducing trade goods and goods available in certain lands will add a bit of realism and a touch of interest to your campaign.  The appearance of traders, caravans, wandering tradesmen, and peddlers will add a bit of mystery and fun to the game.
  Let's talk a bit about the type of person who would run a caravan through the mists of Ravenloft, and the perks involved in such an action.
  Number One:  Wealth!  You can ask whatever price people will pay.  What costs 4 s.p. in Lamordia, say, a good pair of boots, may bring a price of 1 g.p. in Sithicus, for nice little markup that is wholly pocketable.
  Number Two:  Lack of competition.  Not too many want to brave the mists and run the risks of ending up somewhere like Shadowborn Manor or the House of Lament, ending their trading career.
  Number Three:  Vistani Gypsies.  They are naturals to fill a major portion of this niche, since they have an uncanny ability to choose their destination once they enter the mists.  With their wide range of contacts and skills, they have advantages over the common trader.  This little bit will will explain why the gyspy's are tolerated even if they are disliked so badly.

  While there may be big gaps in the items, many traders are drawn in from other lands, sell their goods, and depart, returning to their own lands by the powers of Ravenloft, unaware what kind of brush they had with true evil.
  OK, here's the breakdown of what ships.

BAROVIA-Tuika, a plum brandywine, is the primary export from Barovia, and is actually a big seller in Darkon, of all places.  It is bought for around 12 s.p. a bottle, and sells for around 5 g.p. a bottle.  Another export is coal, and some metals, but with the predations of Jezra Wagner, the amount of mining has began to trickle away.  There is a limited timber export.
BORCA-  Poison, of course, is the big export from Borca.  Fine clothing is another, mostly modeled after the fashions of Il Aluk, with some competitive fashions.  Much of the jewelry that comes from Borca have poison resivors and such in them.  Another export is timber.
DARKON-Metalwork is a big export from Darkon.  Fine, intricate craftsmanship on jewelry, beautifully engraved pottery, and the metal components of farming implements and harnessing.  Small, and easily portable, metal components of tack and harness, buttons, pins, ect. all sell good, and thanks to the melting pot of (demi)human races, much fine work comes out of here.  Cut gems is another export, along with fine cloth and tailored outfits.  Think of Il Aluk as the Paris of Ravenloft.  Fashions for the big cities are set in Il Aluk.  Timber and metals from the mines are good exports of this country.
DEMENTLIEU-Set on the ocean, Dementlieu exports caviar, fish oil rendered into lamp oils, fragrant oils, and fine netting.  One can also buy small boats here.
FALKOVNIA-As expected, weapons are this domains primary export.  While it may be illegal for foriegners to own or carry weapons and armor inside this domain, a steady trickle of arms and armor stills flows out of this domain.  The quality of weaponry and armor is excellent, and of course, sells for a high price.  Not much else really comes out of this domain, with the possible exception of slaves, some of which are sold to vampiric groups for blood donors.
FORLORN-Surprise-None
HAZLAN-From this domain, not much actually flows, and traders themselves rarely pick up anything, or even stop in this realm.  What does flow out are potions and spell components.  Some are experiments, others were traded for components available on the caravan.
INVIDIA-Out of Karina comes rugs, woven, decorated rugs that while bulky, so sell good to the local populace.  Also what ships is dried, salted salmon.
KARTAKASS-Peach Brandy, musical instruments, meeklebrau and fine crystal are this domain's primary exports. Harkon Lucas keeps a close eye on the amount of goods that flow through his domain, and keeps the taxes reasonable and provides the caravans immunity as long as they do not move enemies through his realm.
KEENING-None.  Traders do their best to aviod this domain.
LAMORDIA-This is one of the few mining domains (Barovia, Darkon, Tepest and Nova Vassa are the other ones) in Ravenloft.  As such, they export metals, fish oils, coal and lumber.  A favorite export is Lamordian boots, comfortable, warm, a good, gripping sole and waterproof.  Another favorite is Lamordian wool, often sold in large bolts.  Lamordian wool is always grey, since it will not take any die.
MARKOVIA-None
MORDENT-Glassware is shipped from here, along with blackberry schnapps and crystal figurines.  Lumber is another export.
NOVA VASSA-Horses.  Some of the best horses in Ravenloft come from Nova Vassa.  They export stone, blocks and shale, along with bricks.  They import lumber, since a local fungus causes lumber harvested within Nova Vassa to rot away within a few years.
RICHEMULOT-Nothing is imported, and not much rolls out.  Mostly household neccessities.
SEA OF SORROWS-None.  They mostly provide transportation
SITHICUS-Elven artwork, boots and clothing.  The elves of Sithicus may also sell bows, arrow, and best of all, a delicate brandy that sells expensive, but is considered well worth it.
TEPEST-Livestock and caviar.
VALACHAN-Thick, rich, red ale is exported from here, along with timber, food, and engraved crystal.  Much of the work that comes from here is graceful and elegant
VERBREK-Weasel fur and wood carved implements
BLUETSPUR-None, except insanity
DOMINIA-None, although some find out that they may 'dispose' of a party member who managed to get ahold of a Bluetspur export here.
G'HENNA-Finely wrought bone figurines.  Many purchasers have no idea that the bone is actually human bone.  Some do, and sell the bone to necromancers
HAR'AKIR-Dates, trained monkeys, and coconuts are the only export, along with, believe it or not, sand.  Craftsmen in other countries made exquisite, tinted glass from the various sands of Har'Akir, the color of the glass moderately depending on the color of the sand.  A handfull of blackish-blue sand results in a sea green glass.
THE NIGHTMARE LANDS-Duh.  Nightmares.
ROKUSHIMA T'AIYOO-Oriental style weaponry, philosiphy and items are what flows from these islands.  Tattoos are a favorite, with once and a while a tattoo artist making a round with the caravan and bringing back goods.
SOURAGNE-Goats, snakeskin belts, blueberry schnapps are the only exports of this swampy domain.
SRI RAJI-Silks and crossbows are an export, along with the pelts of wild animals such as puma, tiger, lynx.  Some furs are from were-cats who displeased Arajini.  Rice paper, inks, and fans are another export (Think of it as medival Japan for exports)
ZHERISIA-Not much flows from this urban domain, although metalworking does come from this place.  It's not exactly one of the most profitable domains.  They must import a lot of food, but traders here must be careful, because a big food shipment is worth killing over.  Printing press books, carpets, glass, and small items come out of various shops for shipment.

  As useless as this list may seem to some, it is actually quite useful, and provides plenty of detail to a campaign.  It can also get the PC's a few extra bucks if they use foresight.