I was thinking of this earlier today. I came up with WASD and numeric keypad - + for A B, / for select, * for start.
Then there is the possibility holding the keyboard and playing only with thumbs :-D
I love cursor keys for DOS games, but Gameboy has the d-pad to the left...
So when using cursor keys, the other buttons must be placed to the right. There is only the numeric keypad as option, or am I seeing it wrong?
Granted, not suitable for laptops...