Well, we have now learned more about framebuffer. The puzzle arose from assuming that Linux offers modern video support. True in general, but wrong assumption here.
VBE 3.0 is 8 years old. Linux still has no VBE 3.0 support in vesafb. Vesafb is a VBE 2.0 driver. Two years ago they were talking about it: http://lkml.org/lkml/2004/10/18/143
VBE 2.0 uses fixed modes which are either compiled into the kernel, or assumed some other way. (I'm not clear.) Without VBE 3.0 calls, the video board cannot tell the kernel more than it assumes. We have VBE 3.0 boards like everyone else today. We do not have a VBE 3.0 framebuffer driver.
So, "just drop vesafb and use another framebuffer driver." Guess what, nVidia framebuffer conflicts with nVidia X11 driver. Do you have another suggestion that will not conflict with nVidia X11? The only one we know is vesa-tng.
All we can hope is that grml returns to vesa-tng (because the bugs are gone now?) or Linux brings vesafb up to date after 8 years.
If someone wishes to correct/inform/educate/tip us in some way, thank you, please do.
Mark