CARPENTRY

Carpentry skill is mainly used to make furniture, but not only (scroll down to see a list of the items). As you can see some items require Tailoring or Tinkering to be crafted, thats why you you should thing about having those skills on one char, as true merchant this is very nice idea. Also handy will be Lumberjacking skill, to chop logs yourself. Carpentry skill seems to be easy skill till 80% but then its damn hard to train, of course nobody said you have to train it till GM, all items can be made by ~100% of the skill so 80% +20% from jewel works well. But if you really want to train it till GM, it is very important (if not the only way) to have Lumberjacking skill, chop your logs on your own plus spend all your cash on boards or logs.

Check also: LIST OF ITEMS HOW TO TRAIN
 * Merchant Quest
 * Lumberjacking