I bought a Gameboy Advance online with installed Afterburner. So far I only have the one game for it, but I'm playing around on eBay some trying to buy some more.
The Afterburner really does fix the darkness problem with the GBA. Mine was supposed to come with a dimmer but the place I bought it from decided not to install them (they've actually stopped selling upgraded GBAs because it was too much trouble). I was going to post a link to another site that sold upgraded GBAs, but they've also decided it wasn't worth it anymore.