IMO I think that if you can follow the link that Airheadq provided
Here's and example of a mod.
Ask in that forum were Soulsaber found his keybord you might be able to get one that way.
Although I'm sure you could mod your keyboard, it will be time consuming and tricky to say the least. you would probably need to find some SMT LEDs and either some thin wire like 22 gauge wire and/or some type of homemade circuit board with some SMT resisters on it,etc. it could get complicated to say the least.