> I am coming to the conclusion that right now the -only- splash that works
> in this genkernel is the 1024x768@16...
>
> There does not appear to be any way to specify any -specific- bootsplash
> size. Specifying vga=788 or vga=0x314 does not change it...but gives me
> either a black screen, or an out of sync page.
>

The problem you are experiencing has to do with the initrd you are using.
If you create the initrd with a 1024x768 image (size of the default) then
no matter what vga= option you give it is still going to come up 1024x768.
The kernel isn't smart enough to resolve the fact that the image in your
initrd is 1024x768 and that it needs to resize it to vga=788 (actually it
might realize this fact and issue an error in your dmesg but it doesn't
have the tools to resize the image for you). So if you want the splash
screen to play nice you need to create the initrd with the appropriate
sized image.. or use one with the right sized image. Hope that helps.

Cheers,
Jason