Yap, I also checked the vbios patching post on insanelymac... But IMHO, it is a little bit too dangerous, wait... no..., risky

, and also not challenging enough for myself
As I'm coming from the Linux world, I will check what's happening with their uvesafb and my graphic card/display. If I manage to get some high-and-not-in-the-vbios resolutions, I'm currently thinking about hacking Chameleon and integrating this uvesafb in it... But that's a long way to go