Do you like microphone preamp shootouts?
Yeah, the Brent Averil API 312 doesn't seem to blow away the others like you think it would. But that's the thing. One at a time these sorts of things don't make such a big deal. But when you start to build up tracks it starts to make a difference. Like Alan Douches says, it's an "accumulation of subtleties."
You know what seems cool though? The Little Labs Lmno preamp.
I'm also somewhat curious about the Lindell preamp.
The A Designs 500 HR is a relatively inexpensive 500 rack with power supply (at $300).
Radial makes a 3-slot 500 rack (also in a 1U space) for only $350.