I haven't used them but have seen them in Brisbane recently, I think at Epic Cycles (07 3368 2324), but if not there then Rebel Sport (07 3221 7894).

I think the MTB / shy shorts would be better for 'mingling' as a shamois is still going to wick sweat to whatever outer wear you have and I expect you'd end up with a big (& visible) wet patch on your jeans or cotton shorts...