Hashcode the developer of SafeStrap for various Droid phones like the Droid4, Bionic, and Razr has added Kexec functionality in his latest version 2.11. Kexec is the same process that allowed us to circumvent the bootloader on the Samsung Galaxy S 3 before it was unlocked. This allows for all sorts of mods. One of the main mods that Kexec allows is custom kernels! Hashcode has been working on Kexec versions of Roms and all sorts of other goodies. If you aren't familiar with Safestrap it is basically a recovery that allows us to dual boot. We can run two roms simultaneously. The non safe system would run your stock Rom and the Safe system would run your custom Rom. The addition of Kexec functionality is a huge accomplishment!
You can find it at Rombot.org for now
Further Releases will be announced at Hashcode's Blog