Yeah I've done LED illumination from beneath....
http://forum.arcadecontrols.com/index.php/topic,59359.760.htmlPost 780 pic 1 shows a couple of Tornado spinners lit up from beneath.
I originally built the panel long before button hole mount spinners and LEDs became all the rage, so the method I used is not the most optimal, yet quite effective. Just used a plunge router and a small circular jig that was about an 1/8" less in diamter than the bottom of the spinner knobs to take out about 1/4" recess. Painted the interior of the recess bright red which was the illumination color I was going for. Drilled a couple holes big enough to slip a couple of red flat top 100mah leds up in there from beneath. Then set them up on a LED Wiz and LED Blinky to light up which ever ones are to be used for whatever games. Would've been better to do the backlit from under the CP's plexi panel, but that wasn't an option for me considering I was going at this azzbackwerds.
Should work with a Tron spinner as long as your panel isn't metal. Otherwise those Nephrings should do the tick.