I actually just spoke to my dealer. He was telling me that it's extremely rare for Boulder to actually sell their monoblocks (2150's or 3050's). He said it's simply unnecessary, in most cases. Told me that Boulder almost always sells stereo amps, because they give you 80-90 percent of the performance, and they are more amp than you will ever need. Really, with monoblocks you are paying for a separate chassis and power supply.
Also, he told me (like others have said on this forum), it makes more sense to get stereo 3060 (115k) vs mono 2150's (98k).
The stereos are just that good!