Ive done a few trade shows over the years.. set up stalls etc. Many of the car stalls have absolutely nothing for sale.. but will take orders.
A proper trade show is not a cheap place to have your profile presented.. it is friggin expensive... minimum charge per power point etc. The guys i used to do this with dont do it anymore as the $$$'s were just not there and dwindled away... many car companies refused to display as they were just not getting the return.
I dont see any reason why it couldnt be piggy backed with something like Comicon, but price per stall would determine any success.
So what would you have???

Pinball Rescue maybe selling plastics,
Me with stencils and neon etc
A few spare parts stalls
Restored games for sale
Possible new pins on offer.

It doesnt matter about the forum thing.. AA..AP.. whatever. What does matter though is that whoever is there to organise/ invite for stalls should be impartial. The attempt last time to make expo a 1 forum event was pathetic and its this sort of pettiness that kills the community. People need to get over personal issues and stop behaving like little spoilt children.
You either have both forums profiled or none at all.. its simple.
I only care about someones character and some have displayed a character that is far short of reasonable