...I can't seem to find one for sale anywhere though. The only two I've found so far are on ebay, which is pretty famous for asking too much for vintage equipment. The one up now has a starting bid at $500 and a reserve set higher than that. No information of whether it has been serviced, and local pickup only. There is one for sale in Japan, but the asking price is +$2000, which, even though it has been serviced and comes with a 1 year warranty, seems outrageous...
...EDIT: the speakers I am driving right now are HPM-100s. I do plan on upgrading them as well down the line, but it could easily be a year+ before that happens.