They are simply not common - the require a fairly large room to work well and not be overly-bassy. And indeed they are not inexpensive, which adds to the scarcity. Great speakers if you have the room and setup. The other Harbeth stuff is worth a listen too. I'd recommend the best of their line being the Monitor 30 and the Super HL5. hl5 has more bass, bigger box, but I like the tweeter in the 30 a bit more, plus the size/shape works better (smaller). They are supposed to have a floor-stander coming out @ CES.
-Ed
-Ed