I've had the same problem. I configured kernel v2.6.20. installed it and the screen was vlack. Then I copied the .config file from my older 2.6.14 kernel, and in Device Drivers-->Graphics support the Option "VESA VGA graphics support" appeared after "VGA 16-color graphics support". It wasn't there before, don't know why
So I think that you just have no VESA Framebuffer compiled in your kernel.
Can you access your machine via ssh after a black screen boot? Mine went up correctly.