The investigation I did uncovered
http://www.coralreefecosystems.com/ having the best price at $75. PremiumAquatics also carries the bulb and should price match. Not for sure who else carries the bulb now.
There are several threads on discussing the bulb but the best thread I found was in the Icecap sponsors forum over on RC.
Every 20K rating I've seen at 175W is pretty dismall light output. Even for LPS and such may not be all that useful IMO. Me personally I would probably lean more towards flourescents vs. the higher K MH 175W.