M14P, The biggest hurdle I can see for the expansion of the series is purely the logistics.
While I don't have any solid figures, the disassembly and transport of one aircraft would have to be immensely expensive, especially considering the aircraft is likely to do less than 3(ish) hrs of flying at each location.
I think a feeder series would be a great addition, though not with a pitts!, can you imagine re-rigging the thing at every location after putting the wings back on? I would suggest 15 pilots sharing 3 or so stock Ea300l's or S's. Or perhaps Cap 222 etc.
Yes this disregards issues of personal preference of setup, sponsorship markings etc, but surely more cost effective. There is plenty of the top guys still running around with just the generic Audi or Seat sponsor markings, and no individual sponsor.
Which leads me to the question, how does the series remain financially viable? for both RB and the competitors?