Bisecting sometimes requires numerous reboots - and having just 1 grub entry for all created kernels would help, eg.: currently we do have "kernel-genkernel-x86-3.11.0-rc5+" but it would be nice to just have "kernel-test"
The newer genkernel can use grub set-default to ensure the new boot goes to the latest built kernel. I used it for bisecting an issue recently.