Thats a different debate, personally I would happily pay 50% extra on my yearly subscription if it meant we could tell ALL the traders to get stuffed with dictating rules to us about who can and cant sell stuff on here.
The risk then though is it becoming too attractive to scammers if its totally free.

So for the small trader thing to work I think it would be fair to make the requirement its only active forum members who have been signed up 6 months minimum and made at least 500 posts or something like that, to stop the nigerians thinking it gives them a good market, make it so its harder to get on here than ebay and it should keep the scammers off.