Here is the part of my XF86Config that relates to resolutions. Note that even though the only resolution specified is 1024x768, it goes to 640x480. The Red Hat config is identical to this one, and as stated above, it works fine. I have even chrooted to its X server, and it goes to 640x480 under this kernel. And if anyone knows of a stock kernel that has devfs support (required by gentoo), let me know. Thanks.
The full XF86Config is at http://home.comcast.net/~ryhudd/XF86Config
I now realize why genkernel didn't work right! I forgot to use hotplug. I'll try my newly recompiled kernel, and if that doesn't work, I'll try genkernel.