The small Alps push switches can be had from Mouser for 70 cents @100 pieces. P/N 688-SPUJ190900
For led's,
www.superbriteleds.comThey have most colors and a special incandescent color temp led that is ideal for replacing incandescent bulbs for that old time look. For a modern look, use standard white leds.
For SSL stereo buss amps, I use a matched pair of Hitachi 2SA2545 transistors (1/2 the noise of the LM394) and a National LM6171 opamp at 3600 v/us slew rate, that will open up the mix like after your ears pop landing in a jet. Good caps with quality film cap bypasses are also helpful. Then dump the 074's in the monitor card with LT1359's and then you can hear it. Dump the Roederstein bipolar electrolytics with low impedance polarized units properly oriented. Bypass those with film caps. Replace the 10 uf cap in front of the VCA with 47 uf, then you get some low end and remove some phase shift.
Be happy.