hmm not sure, than again is trusting other sites that you are not use to dealing with.
I sold my old equipment including one of may macs on ebay and brought my rebel from ebay. No complaints at all. I dealt with a good/nice seller there for my rebel.
here is a link to the ebay store/seller I brought my camera from if u wanna take a look.
I'm only curious... but what are your concerns with ebay? I trade all the time and have never had any problems. Ebay presents a worldwide market and I'm sure would offer the best opportunity.
I'd trust ebay miles over anything else out there. Just exercise a bit of common sense and you won't get screwed over. You can't expect to be babysat completely when trading with other independent individuals though, it's no safer than any other marketplace (real or otherwise).