Ray's has been going in the states for a long time now (although I think the pump track is new). There used to be an indoor place in Sheffield called Wheelbase which used dirt rather than wood for the tracks so they could vary the layouts easily each year. Think it went bust a few years back now, so maybe not an easy business to make money out of? I guess if you found an old aircraft hangar or similar you could have some nice runs though...
I was at the goodwood festival of speed a couple of weeks ago and they had an "action sports arena" show. this was the red bull display team and included motorcross, trials bikes, monkey bikes, BMX and mountain bikes. Danny was part of the show and he was amazing - although the stars were the motocross guys who did the most amazing and scary stunts !! they also had dougie lampkin on a trails bike (anyone old enough to watch "kickstart" ?)
see them here :