It seems that nobody currently markets the sort of pre-built rear wheel I currently want--one with a moderate quality hub (e.g, IRO/Formula) and a better quality rim (e.g., Mavic Open Pro). I've concluded from personal experience with the IRO hub on my son's fixie that I really don't need to spend four times as much money for a Phil hub and I really like Open Pro rims and double-butted spokes. There are a lot of deals out there for pre-built wheels with Formula hubs, straight-guage spokes, and lower quality rims (Mavic CXP22, Kinlin, Velocity, Alex, Weinmann, etc.) but not the combo I really want.
Of course, I could just buy the parts and have a rear wheel built up from parts, but as we all know, the cost would be close to an IRO complete wheelset (prices with shipping: hub--50.00; OP rim--75.00; spokes--35.00; build at LBS--30.00). I would gladly pay 140.00 for such a wheel, so why is nobody selling them. It seems like a logical market niche is being ignored.