All units are US/Canada
I've got Gameboys all over the place, but here's what I've found so far:
DMG - Gray
G22484694
G19299578
I can't say much about the DMGs themselves because I may have [accidentally or otherwise] swapped cases. I haven't done any backlight modding on them.
CGB - Red
This one came off; damn. I have another around here somewhere.
MGB - Black, no power indicator
MG112015?31
Serial came off, but I managed to dig up a picture; it's pretty tattered, so I can't recognize one of the numbers. Might be a 5 or 3.
Take a look if you want... not using BB code because it's a rather large image.
http://i732.photobucket.com/albums/ww32
MG4607.jpg
I did a backlight mod on this one; fairly easy.
I have a strong feeling that the DMG serials just sequential in order of manufacturing.
For laughs:
Atari Lynx W29C5007349
Atari Lynx 2 Y215101440?
Sega Game Gear - Black 031649809
Sega Genesis - Model 1 31X53287
Super Nintendo - Mini UC20271167[4]