The solution depicted below is built into a 19", 3 HE case. The heart is a Power One linear power supply (HDD15-5-A) with lots of additional stuff around it. It provides +15V, -15V and +5V, all with 5A. I included overcurrent protection, overvoltage protection, mains filtering (spikes & such), 2 fans with temp regulation and 6 indicators to have control over all the voltages and currents. These leave the supply through 4 connectors on the rear.