ClassicRGB buttons: $7.50 each x 34 = $255
ipac UIO: $99
LED Blinky: $25
Extended wiring harness: Around $20 whether you build or buy
Keep in mind shipping, as well as the fact that the ipac UIO is short by 3 outputs.
OR, GGG:
electric ice 2 buttons with RGB led's: $5.70 x 34 = $193.80
UIO can't drive those LED's because it overdrives them by 2ma and they degrade rapidly (this is what I tried).
So for 102 outputs, you need 3 LEDwiz's @ $44.95 each = $134.85
You still need LED Blinky and some extra wires, although extending them is not horribly expensive since you don't need DuPont connectors with the LEDWiz, so about $30-35.
Add shipping and you are getting really close to $400 again. Chances are with 3 LEDWiz's you need a USB hub as well, which would put you over.
If you plan ahead and don't try to retro this into your build, you can save on the cost of the original buttons, about $100, and if you go with the UIO, another ~$50 in an encoder, so then it is only hitting you for around $250 extra.
Plus if you haven't done it before, you will have dozens of extra hours into wiring and programming.
(P.S. I only went the basic 4 player with trackball and spinner, no other controls and still had around $1250 into my cp with full RGB. By the time I added aimtrak's, bought pedals that I never put on (and an apac for the pedals) and completed the rest of the cab, I totaled in at $3k)