If you are interested, I just made a couple of rack mount DS5-type units and ordered the parts from Mouser (
www.mouser.com). Here is the parts list including the transformer:
Mouser #:611-7201-021
Mfr. #: 7201P3YZQE
Desc.: Toggle Switches ON-ON DPDT FLT $7.68ea.
Mouser #:568-NC5FP-1-B
Mfr. #: NC5FP-B-1
Desc.: XLR Panel Mount Connectors 5C FEMALE BLACK $11.52ea.
Mouser #: 660-CF1/4LT52R203G
Mfr. #: CF1/4LT52R203G
Desc.: 1/4Watt Axial Leaded Carbon Film Resistors 1/4W 20K 5%TR $0.34ea.
Mouser #: 75-TVA1213
Mfr. #: TVA1213
Desc.: TVA Axial Electrolytic Capacitors 25V 2000uF $4.99ea.
Mouser #: 833-RB152-BP
Mfr. #: RB152-BP
Desc.: Rectifiers - Bridge 100V 1.5A $0.34ea.
Mouser #: 802-P-8396
Mfr. #: P-8396
Desc.: Power Transformers Single Secondary $10.94ea.
You can use the above schematic and build it that way. I got the single rack space 19 boxes from Markertek. I included some other stuff (front & back outputs, mono/stereo switching, effects loops, etc.), but this will get you going.
Thanks!
John