700 wheel w/disc hub
 

I'm looking for 700c front wheel w/disc hub, 32-36 spokes and OP-class rim. Do I need to have one built, or are these available off the shelf somewhere?

Here is the only one I was able to find, although I didn't look that hard. If you look in places that are pushing 29" mountain bikes, it isn't too hard to find wheelsets, but it doesn't appear to be easy to get just the front at a reasonable price. If you end up getting one built, I have had good luck with Velocity Dyad rims for 700c disc brake wheels, have also built with Alex Adventurer and WTB Dual Duty.

http://www.cambriabike.com/shopexd.asp?id=24910

My bike is a Redline Conquest with disc brakes, the wheels it came with are Velomax Sagitta's. Only sold through Redline dealers, never on the web, but they're pretty common on ebay.

Front wheel is much easier than rear wheel because the drop-out spacing is the same for road and mountain.

I'm planning on just building one. I find building wheels pretty easy, the very first one I built is still on my bike and 100% true with no touching up after 4500 miles. I just bought a spoke wrench and built a truing stand out of 2x4s and shelf brackets. AEBike has a basic disc hub and Alex rim for < $50, and building a wheel is just an evening in front of the TV.