STR based Glaiver/Blader = Hunter or Trader
STR (Pure/Hybird) Bow = Thief/Trader(They got range)
INT (Pure/Hybird) S/S = Thief/Trader
INT (Pure/Hybird) Spear = Thief
These are all in personal preference, and the above is just what I think what would be best for a trading caravan. A good tank to hold off all the thieves would be useful, and having range as a thief is definitely a + (having range in any situation is a plus

). But to be honest any build can pull off any job.
BTW besides trading, you should w8 till higher levels till you pick a job. Being a level 20 thief or hunter is no fun
