I've been in a similar boat while researching "what's needed" for a Virtuoso Quad-Eight desk in Tulsa (the last desk Quad-Eight ever sold). It's a 36 x 24 desk.
The original power supply was a huge affair, with +/- 18 V at 10 Amps, +24 at 10 Amps....twice! IE, double the amounts listed since the internal desk PS distro was essentially split into two halves.
Unfortunately, Quad-Eight used a (now) Unobtanium "hybrid brick" from Lambda. One had failed prior to the current owner's purchase, so a "sidecar" supply had been added. In recent times, other of the Lambda bricks have failed, and I've cobbled it together with supplies available from the unused automation system.
My "current" (no pun intended) plan is to build up a pair of 3RU chassis units. Each will house a pair of 15 Amp 15 VDC International Power open frame modules (with the Amek mods to allow 18V operation, and a "slow down" of the overcurrent trigger due to the DC inrush...more on that later) and one International Power 24V @ 12 A module in each chassis.
In one of the cabinets, I'll also stash a small 48V @ 0.5A open frame module for the phantom rail. (That will supply at LEAST 35 mics under the worst case conditions, which is pin 1/2/3 on the mic input all shorted on all inputs).
On paper, so far, so good. BUT, each of the three modules weigh 20 Pounds each, so that's 60 pounds in each rack box. The modules are too long to mount sideways, so the rack box has to be approx. 20 inches
deep. Now I have to worry about the integrity of the rack cabinet due to the weight and depth.
On top of everything are the air movement specs for the open frame modules. I've been in contact with Tony Kordyban, who wrote an excellent book about electronic equipment cooling:
http://www.amazon.com/gp/product/0791800741/sr=8-4/qid=1144831111/ref=sr_1_4/002-1161618-6534464?%5Fencoding=UTF8
So, I've also had to add into the equation some Papst fans to move air through the rack cabinets.
All in all, it's NOT going to be an inexpensive project.
I briefly pondered switcher supplies, but I find them to be unreliable in my part of the world (thunderstorms), and I've had serious problems with multiple switchers each "whining" at their own frequency, thus creating beat frequencies as each supply generates square waves at slightly different frequencies.
DC Inrush....
One commonly overlooked issue is the existence of a bazillion filter/iso caps hanging from the DC rails. That is a MOFO load that the power supply has to see when a large desk is powered up...essentially a huge short-circuit. Amek and International Power teamed up to create a solution, with an extra cap (and resistor?) on the power supply module to slow down the over current "triggering" as a large desk was powered from "cold".
Bri