How about a new section called "Feedback"
You post up a review of your transaction with a seller. You can state exactly what you bought or just be vague and say "Great to do business with, great communication and really fast shipping, I wouldn't hesitate to do business with him again"
You can also post a poor review , but keep it civil
The seller then responds to that review if he wants to defend a poor review.
Nobody else can post on the thread except the 2 parties involved. No 3rd party defense or "I can't believe that" posting. keep it between those involved.
If the seller did a run on an item and ripped everyone off, everyone post their own seperate "Feedback". Don't jump on the bandwagon. That way his "Feedback" will have several problems instead of only one.
For example;
1st post from buyer - slave1pilot did a really poor paintjob on my jetpack. the weathering is way to light on it & I wanted it dirtier.I feel he ripped me off because I paid way to much for what I got. I will not do business with him again.
2nd post from seller - I apologize if it is not what you had expected. I tried to paint the pack as accurately as I could. I can do additional weathering or refund you a portion of your payment. PM me and we can discuss options.
3rd Post from buyer -PM sent
4th post buy seller - agreement reached
5th Post from buyer - Yayyy I'm happy now
Just an idea.