interesting. here's the big question for you:
who's backing this corporately?
i'm not going to beat around the bush here. this will be an expensive venture. simply to construct a facility your friends better be stocked up with at least half a million dollars. after which, they'll have to buy insurance. ask any action sports facility in Canada what their insurance rates are. next you'll be looking at land opportunities. now, you're saying between brampton and orangeville. to me this means the caledon area and that my friend isn't cheap at all.
you talked about user fees and number of users at a time. you said 10-20 users i'm guessing per session. how long is each session and how much are you going to charge per session? so let's call a session 2 hours long; at $25 per session with 15 people per session you're looking at a gross profit of roughly $375 per session and 8 hours in a day, so $1500 gross. next you need to look at user frequency, coaches, medical staff, etc...
what this boils down to, is that unless your friends are looking to invest upwards of possibly a million dollars or more in initial start up capital, this thing won't happen because let's face it, no bank is going to issue a loan based on their business plan. without a name like Woodward backing this thing i wouldn't hold you breath people.
Woodward became successful with their business by designing a sick skate park and made it a destination camp for skateboarders and bmx riders. from there they increased to accomodate skiing, snowboarding, inline, mountain biking, gymnastics, tumbling and cheerleading. they've been around for over 36 years and have it down to a "T".
the closest southern ontario has ever come to having a facility like this was when the new owner of talisman pledged to build a water ramp/trampoline centre in the collingwood area in conjunction with FSO and Gymnastics Ontario. unfortunately a lot of us know how this went.
call me a downer folks but this is reality. if this somehow happens, i'll be the first to admit i was wrong.