That sounds very good, or maybe Bitcoin Forum could maybe operate its own Exchange given time.
Yes, there'd be the need to limit what is available and to whom, but it could solve a lot of problems like bickering and bad feelings:
Person A asks for a maximum of x in Bitcoins
Person B says 'okay, put your PayPal or Debit Card Payment in your Exchange area and lock it' - that means only the payment/FIAT put in can be taken out and nothing else.
Person A then says 'okay, the payment is active' and presses the 'Exchange for Bitcoins' button.
Person B then presses the 'Exchange for Cash/PayPal/etc.' button.
The exchange is timed to take no longer than an hour, with both parties receiving points which will go towards their credibility and respectability as buyers and sellers - the better the rating, the more trustworthy the person.
Just a thought...