Agreed. Separate Lefty section I can understand, I can imagine being a lefty is a pain and it's not like one chooses ones handedness. Beyond that one binary choice which is fairly easy to make I'd have to vote no. Besides, most manufacturers make lefties feel like lepers already, so shoving them off into their own little sub forum shouldn't feel like too much of an imposition
Making more subfora would quickly become messy and increase the possibility of misposts, increase the amount of moderation/adminstration required. If you want a better marketplace with the granularity which could quickly develop then it would need to be an actual marketplace, using items with attributes which can be searched against/filtered. Trying to replicate this with simple subfora is like trying to build a house with a fork, knife and spoon.