Glad you like the idea behind GB Enhanced 
You can thank AnyOldName3 for suggesting it; the concept intrigued me. I actually stumbled upon both projects a few months back. Looks like I'm not the only one who had that idea. Fwiw, there was a proof-of-concept GB emulator that did allow HD tile replacement, but it was incomplete (and I don't think it handled colorizing DMG games). I'm not exact the first when it comes to the GB, but I guess I've gone the farthest.
GB Enhanced only handles 1:1 tile replacements, but support for arbitrary scales (2:1, 3:1, 4:1, etc) is already implemented in a new branch. There are still some finishing touches that need to be applied, but it works. GBC tile replacement isn't supported yet, but that's coming soon. A shame I don't have screenshots on hand to show you any progress.
You can thank AnyOldName3 for suggesting it; the concept intrigued me. I actually stumbled upon both projects a few months back. Looks like I'm not the only one who had that idea. Fwiw, there was a proof-of-concept GB emulator that did allow HD tile replacement, but it was incomplete (and I don't think it handled colorizing DMG games). I'm not exact the first when it comes to the GB, but I guess I've gone the farthest.GB Enhanced only handles 1:1 tile replacements, but support for arbitrary scales (2:1, 3:1, 4:1, etc) is already implemented in a new branch. There are still some finishing touches that need to be applied, but it works. GBC tile replacement isn't supported yet, but that's coming soon. A shame I don't have screenshots on hand to show you any progress.