Regarding USB booting, I used an old optical drive instead.Good enough for me. Same for the slow USB keyboard on GRUB, I'll just plug a PS2 keyboard when I'll (rarely) need to. Of course, if it's super slow when I type my passphrase, that's a real problem then (unless I find a good, silent ps2 keyboard).
Kepler is about the GPU? Unfortunately I don't have this one.
