no more liabiilty than the current forum where members request paid services.
What if a paid product was put into this hypothetical forum - and was then later discovered to have serious security vulnerabilities which lead to the exploitation or destruction of several forums. vB.org (Jelsoft) could then be held liable for endorsing or advertising this product, or for even allowing it to have been on the forum at all.
At least with the Request for Paid Services forum, any blame rests solely on the individual who took up the request, not on Jelsoft or vB.org. With a forum like the one you're suggesting, blame would rest on BOTH Jelsoft/vB.org (for allowing the product to be published here) and whoever the product's developer was (for the existence of the exploit).