This Logitech G710+ has o-rings already under the keys. It's on sale at Best Buy for ~$120 plus tax:
Thats the one I was referring to, seemed to be a decent keyboard but its too large due to the stupid macro keys.
ended up getting a killer deal on a corsair k70 which IMO is the perfect size for a keyboard.
When looking at keyboards I see a lot of illuminated keyboards with complaints over the LEDs dying. --- Laugh, and the world laughs with you. Weep, and you weep alone. The armory of god is guarding me but all you can see is holographic artistry.
I've heard of people using dental o-rings for braces. Some companies market o-rings for putting on mechanical keyboards. I guess they have different heights to set different key travel: http://www.wasdkeyboards.com/index.php/products/keyboard-accessories/cherry-mx-rubber-o-ring-switch-dampeners-125pcs.html#ad-image-0
Amazon has them too with several reviews: http://www.amazon.com/Cherry-Rubber-O-Ring-Switch-Dampeners/dp/B00AZQ2OF8/
I thought different densities of rubber o-rings were available too, but my old bookmark expired. It might be fun to just try out whichever little o-ring you have laying around if they are small enough to fit.