I'm glad you've seen my site. Hopefully you checked out Rob Hill at ideas-na.com too. Rob is a bit closer to you in disease experience; yet he is still managing to do REALLY BIG mountain climbs.
As far as having an ostomy and doing sports go: I wouldn't have it any other way. Sometimes the pouches leak during workouts or races, but sometimes they leak for no reason too. Nothing is perfect, we just have to adapt. Anyone I know who has had IBD and then done the ostomy surgery has had a really good recovery and their health has improved drastically. Ostomy management is pretty simple once you get the hang of it. I have done a lot of skiing, rarely had any problems with the pouch; and its really easy to go in the wild when you have to without freezing the tender bits.
One bit of advice I would give you if and when you have the surgery, don't compromise your quality of life for pouch wear time. The products are expensive for certain, but life isn't much fun when your sitting on the couch for fear of springing a leak. Don't worry about the small stuff, and believe me after a time, leaks will really be the little things.
Feel free to contact me anytime.