As a newcomer to microlighting & aviation in general, I can possibly offer up my views on such an event, coming from an aviation newbie.
I have currently little exposure to anything other than my training on an Aquilla 582 at Rhino Park, the pilots I have met there, as well as the various aircraft I have seen there, Microland (where my trike stays hangered until I get my licence), RAASA offices, and Comet Aviation Supplies at Rand airport. I know of Buzzcom, but have never been there yet, as I'm still waiting for that ship to come in sothat I can afford to buy stuff there
. The point being, I am CRAVING an expo designed for us microlight & LSA aviators 
Having seen a few airshows & fly-ins, I can definately say that there is not enough (if any) aviation exposure to the public, other than large airshows. There is definately an interest, as I was amazed at how large the attendance was at the last Rand Airport & Swartkops Airforce Base airshows. To hold an event for LSA & microlighters at a small, far out venue will not do justice to the potential interest it can attract. I organize events as part of a hobby, and I can tell you a few important things about a successful event:
1) It must be centrally based (i.e. not too far to travel from a major city)
2) It must be organised and advertised well in advance (3 to 6 months gives enough notice for people to make plans)
3)It must be advertised beyond the scope of this forum & the usual aviation magazines to attract the untapped market, and pilots who do not use those mediums
I'm not talking about a huge budget epic airshow, but rather something that will attract people who have always dreamed of flying, but never persued it because they though it was too expensive. It could also attract a few commercial pilots (a good example is an old friend of mine who I met up with the other day. He had no idea that Rhino Park, Kitty Hawk, or LSA flying even existed, and since talking to him, he's hooked!). Its great to have the usual suspects rock up at an expo, but to make it truly successful, you need to attract those who are unaware we exist. 2 Years ago, that's where I was, so my point of view is put across based on my experiences & expectations of the sport.
What I'd personally like to see at an aviation show like this would be (call it a wish list if you like):
1 ) As many variations of trikes, LSA, Gyros, helicopters, motor chutes and anything that flies as possible on display
2 ) Supplier stands of anything from pilot training to books, dvd's plane spares, radios, helmets, headsets to flight suits & jackets (with ready to sell items on display & with credit card facility)
3 )Training school stands that offer demo flips
4 ) As many microlighters, gyros, LSA, helicopters etc. as possible to fly in that can fit on the airfield
5 ) Maybe a short nav flying competition as an alternative to an 'airshow'
6 ) Workshops from suppliers (eg. engine maintenance demonstration by a rep. from Rotax)
7 ) Live kit builds (those busy with kit planes can bring them and carry on building them while the public watches)
8 ) Concession stands (hot dogs, hamburgers, drinks etc)
9 ) Jumping castle for the kids
10 ) Last, but not least - a bar!
Maybe all the items on the list is being a bit ambitious, but that is certainly an aviation show I'd want to go to!
It's a fantastic idea, and gets my vote
If you need a hand, I'm pretty good at organizing events
