Don't forget Western Digital. Up until recently, their "expert" line of drives were just rebadged IBM 7200 RPM Deskstars (I know this was true up through the 27.3GB WD Expert, and I believe one model after that). In my experience, those drives, like their deskstar cousins, will handle 37.5MHz, and even 41.5MHz (although I don't recommend it) just fine.
The reason I mention this, is that there are still a LOT of these drives out there. For example, Sams recently clearanced out the 20.5GB models for $60 after rebate.
Good luck,
Nack