Awesome! The speed is very impressive.
I noticed something funny: I tried playing a GG game (Psychic World) and despite the broken palette, it actually worked sort of! But the funny thing was that you could see not just what would've been on the GG screen, but also outside of that area, as if the game was running on a SMS. The GG version of Sonic & Tails also had almost perfect full-screen
So I've been thinking, maybe once you have GG mode worked in, it might be worthwhile to look into this and possibly create a hybrid GG/SMS mode for GG games? With the right palette, but drawing the stuff outside of the GG screen as well.
I don't know of any emulator that does this, so it might even be some kind of innovation.
A minor complaint:
While I really like the interface, the controls are kind of counter-intuitive.
I keep pressing B to exit menus, seeing that I'm used to it after playing zillions of games that have A = accept and B = cancel.
And I'd like to use left and right to change options instead of A/B and L/R to skip one page up or down.
Maybe it's just me, but I think it's more intuitive (this goes for both DrMD & DrSMS, obviously, since they share the same interface ;-) ).
P.S.: A speed-button to skip 100-times-seen-already intros and cutscenes would be handy!