OK guys, on to the Elite 4 (thanks Drock, it looks good). I'll post a few more progress pics for this one.

Cut an LED strip into 2 sections, each slightly less than 21". Then solder on 2 very short lengths of primary wire. Test with a battery.

Cut some lengths of the paper-thin flat speaker wire and solder it onto the primary wire. When I say paper-thin, I mean it - this stuff is less than 1/16" thick! Test with a battery.

On the RCA endplate, remove the 2 hex screws holding the aluminum plexi retainers

On the power/speaker endplate, remove the 6 larger and 3-4 smaller hex screws. You can now take the endplate off and the slide/lift the aluminum plexi retainers off.

Remove the 10 hex screws holding the plexi in. They'll probably be under some tape, unless your amp has been serviced.

Take the time to blow out your board and clean both sides of the plexi.

I don't trust the adhesive backing of LED strips, so I first laid down a rubber adhesive double-sided foam tape along the underside of the chassis. Basically right under where the aluminum plexi retainers sit. I know this tape retains its stickiness under heat too, which is essential because this area will get quite warm. Then I stuck the LED lengths to the tape.

Here you can see the speaker wire hanging out of the amp.

Screw the plexi, retainers, and endplate back in. Position the wire such that the endplate is compressing a flat section and don't cover any screw holes! Remember not to overtorque.

Solder the wire ends together whichever way works best for your install and then do the final battery test.
All done! The 4 looks even better than the 2 all lit up, thanks to the extra board components. This looks amazing in person guys, photos can't do it justice. It really brings these amps to life cosmetically.
I decided to do blue LED's because the rest of my install is highlighted in blue. The color-changing ones would be cool though and I hope someone takes that on. I might do a frosted emblem down the road, but right now I feel like just highlighting the board with LED's contributes to the classy looking nature of the amps without being too flashy.
If anyone wants some of that thin flat speaker wire, I have a ton left. PM me to send a few bucks to my paypal and I'll ship a few feet out.
Hope that helps guys!