Is there a list of what items certain merchants buy or won't buy from your character? I'm playing a tech character and I have various things I've made and would like to sell to get the money to buy the schematics for the cooler items. But I keep getting stonewalled by the shop owners. I've put two points into haggle and got apprentice training, but no help. Any help is greatly appreciated.
I do not know of any such list (though I'm sure there is a .mes file or another in your Arcanum directory), but shopkeepers generally don't buy things that are too far outside their own stock so to speak (mages won't buy technological items etc). You need Expert Training in Haggle before you can sell everything to everyone.
The Prima Official eGuide has complete lists of what each shop sells (+what is the probability of an item appearing in stock) and not-really-complete-but-still-quite-useful lists showing what can be sold in those shops as well.
Until you get haggle master in which case you can sell anything anywhere. Then again unless you are a mage there really is no reason to go full haggle master as it is fairly out of the way.