Thanks for the reply- there doesn't seem to be any play in the wheels, and they don't turn absolutely freely. The weird thing is that once they cooled down a bit, I could turn the wheels by hand (although they were not entirely free)- doesn't seem like the brakes were sticking badly enough to cause that much heat after only 10 miles.

But it also seems that if the wheel bearings were that bad, then there should be some indication other than extreme heat (like the play you suggested, or some wobble while driving, or something).