Yeah, I think the biggest thing would be deciding where to have it! Off the top of my head, we have creators from Canada, every part of the US, Chile, Sweden, Australia, lots from the UK -- whereas I have trouble justifying the travel cost from the eastern coast to the western coast of the US for a con unless I think it's gonna be a SUPER profitable con.
So you could probably get a meet-up of Tapastic creators in the area, and a Tapastic meet-up at an existing convention that a lot of Tapas folks are gonna be at might work really well! But it'd be tough to get a majority of creators to travel a long way to a brand new (untested) convention unless you were paying their way.