Sometimes I'll see a wheelset with exactly the components I want for way less than the component cost- like a couple of years ago when Performance was selling Ultegra hubs with DT Competition spokes and Mavic Open Pro rims for $199 a set. I bought 3 sets. I took 'em apart and rebuilt 'em. Handbuilt wheels for cheap. Woot!
These days, they usually cheap out on the spokes- no-name straight gauge. So for good- buy your own, for cheap, buy the factory wheels and rebuild em.