I think there would be definite interest, especially if people know something will definitely go ahead and be worth it because:
A) There are often ideas for a show like this and it never eventuates so i think people are sceptical about the idea.
B) It is not worth it sometimes. No offence at all to the guys who did the last one at Mansfield and i appreciate the effort's of everyone involved but it was advertised as having more sellers and like it would be bigger...i turned up and there were four stalls at most in a tiny room with a few different boxes to buy (mainly 2012 champions) and some singles.
I stayed about 2 mins and then left. Thankfully i only lived 5 mins drive away but i can imagine that people who drive a long way may be pissed off to find that a few stalls. As i said, no offence to the guys involved, what they did was great, what they needed was others following their lead....it isn't worth if there aren't more sellers who are willing to be involved and who follow through on their promise to be there.