Onion's right it's completly possible but unless your a total pro when it comes to electronics then i woulden't try it cuz it wont be a easy or non-tedious job, it would be cool though.
Custom case window : Done
Custom japanese case dremil engraveing : Done
Controller analog led swap/hooked up to vibration : Done
Memory card windows : Done
Memory card interior LED : Doing it next weekend
Controller plug window : Doing it next weekend
Conrtoller plug interior LED : Doing it next weekend
Controller case LED's : Were in but they were to dim so im gonna get new one's
ps2 interior case LED's :In progress
Power/reset LED swap :In progress
LED fan swap :In progress
Custom N64 NES case : Done but 2 of the 6 led's died not sure why i'll fix it later.
My favorite anime board http://animeboards.proboards19.com/