I am at the beginning stages of Eador (single shard/scenario) and one of my hearoes met with the trader, and had a look at the goods he's selling, and some of the stuff I want quite badly, but have way too little money and gems to afford them. Is there any way to meet the trader again, in that province? Or is there a chance that those goods will be then located in one of the locations??

By game logic - trader is a rare, always hidden, location in the province with self-destroy on exit.
You can find another trader during exploration, even multiple in the same province, but you can't find the same trader twice.
His goods aren't moved anywhere, but you can get lookalikes from sites.

Thanks a lot.... for the bad news ;) Looks like I can give up hope to find those artifacts again.