Here is a video of a GameBoy Color being played on an LED matrix. He has built it up to 140×140 LEDs so far and it seems to be going well. He needs to add the final 20 LEDs to get the 160×140 resolution of the GameBoy. He notes in the comments that he had some problems with dead LEDs in the boards he got from eBay. Trying to remove the dead LED with a hot air rework station resulted in massive damage to the board. At one point he says that the power consumption is 1KW when showing all white. Wow, that’s a drain.
[Kevtris] gave us some more info in the comments with a link to the build pictures in his blog.