Cool idea! I hope it can happen. It sounds like a rather big deal, as many cities are included in the possibilities. Are you thinking formal convention type deal with hotel reservations, meeting hall, meals etc? If so, that would be a massive and expensive undertaking. You would need hundreds of attendees to break even.
You might consider an HEAS-like gathering held at some mover and shaker, spark plug type fusor guy's farm, business or home in one of those cities. Even then, about 20 folks might be desirable as minimum attendance. However,......... Jon Rosenstiel had a single west coast fusor gathering at his home a number of years back. Even though he had only 3-5 folks attend, in was very cozy and very one-on-one. They had a blast.
I have about 50 attend HEAS/TCBOR event each year since 1989. Since 2003, about a quarter of those attending are fusor folks.
Again, all the best
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.