OK, this is probably one of the greatest iPhone mods we've seen to date. Featured on Adafruit, this mod uses a "trademark-infringing" replacement back and some other parts to make the Apple logo on the back of an iPhone 4 glow. The modder, Becky Stern from Adafruit, even put a rainbow color decal behind the logo to give it a more retro look.
Check out the original post on Adafruit for more details, and watch the video below for full instructions (love the black fingernails, Becky!). This is definitely not a project for the timid or inexperienced.