I believe what you are describing is the original Honda Cub motor and it was originally an add on motor to the rear wheel of a bicycle, and sold just after the War. Mounted on the outside though rather than inside the wheel. With luck see photos belowA long time ago I was in a Honda Motorcycle Dealership and they had a bunch of old restored 1960's Honda bikes on display in a special room. One of the bikes was from the earlier sixties and it had it's motor built in the rear wheel like the front wheel shown in that Revo. Honda actually sold them before the 50cc step thru bikes became an icon of the 60's. I can't remember the name or model number of it now but it was quite a light weight bike.
This concept isn't anything new, building internal combustion engines into the wheel(s). I think it was being done over 100 years ago.
That little Honda was probably around 50cc's and the rear wheel looked like it had a hub cap over both sides to cover the motor.
Anyone knowing what it is, could you please post a photo or model # of it.
Too bad these aren't out there being sold and used. Or that they don't work well. The idea is incredible. I'd much rather have a nice mountain bike that just had a different front wheel with a 2-stroke inside of it. Vapor ware sounds right though, since no one seems to actually own a working model.