The combined total amount not paid for now is well in excess of 35BTC (mine was 30BTC alone). I imagine he had a swell of orders from all of us at once and then, after seeing the total he could make (I'd estimate we're looking close to £700 here - maybe more) for 'free' without giving the BTC he saw the opportunity as too good to miss. He's been on the forums multiple times since and hasn't responded to anyones PMs.
It's possible.
Another factor that made me believe he was honest is that I PMed him asking for 50 BTC, and he replied that the maximum was 35 BTC per customer at the moment. What kind of scammer turns down free money like that? I understand it's necessary in the early stage of running a Ponzi scheme, but not in this case.