I remembered
this thread and am pleased to tell you that there is more.
You probably know of Nintendopella. They don't have many songs yet, but what they have, is cool.
www.nintendopella.com
I recently discovered Metroid Metal. What can I say? It's Metroid and it's metal.
http://www.metroidmetal.com
I haven't listened into these guys, but people (on the metroid metal forum) say they're good.
http://www.toolzbydaman.com/mp3z/Minibosses/ or
http://minibosses.com
After googling I got this:
http://www.vgmusic.com/music/console...x-classic.html
A lot of NES midis. Not super, but perhaps nice for nostalgic reasons.
Have fun.
And feel free to search more cool game music and tell us about it.