After someone posted in this thread a GBP that looked like the original GB, I decided to try and get one. They're not cheap on eBay, so I took a chance on Amazon and found someone selling one for $40 and figured what the hell.
What arrived worked, but was a little beat up, and must've had the screen cover replaced at some point, since it wasn't the correct one.
So, some Googling for replacement parts, stickers and screen covers, I took it apart today, gave the shell and buttons a good soak in some soap and water, replaced the pads beneath the buttons (though the pads underneath B/A aren't lining up quite right and the A button sticks a little) - and I think it looks pretty good! I really want to do the backlight, but I need to get a little more comfortable with a soldering iron first.