Just an FYI, but I have an ROM from a local outfit that would do the holes on a small time basis for $37.50 a case. That's about $55-$60 counting the 1455N1201 case itself. However, the local guy is not prepared to do quantity, but if that's a reasonable going rate for onesie-twosies, Hammond might even be better with a quantity discount.
This would include:
Case Lid: 5 - 1/8" holes, 2 - 3/4" holes
Front Plate: 1 - 7/16" hole, 1 - 5/16" hole
Rear Plate: 2 - 5/16" hole, 1 - 1/2" hole, 1 - 3/4" hole