PrelinkToKernel is a new app that is able to extract the kernel from the kernelcache/prelinkedkernel of 10.10.x and newer (El Capitan too, of course).
This app forexample can help you to create your "restored installer" where the kernel is not available: just extract it from the kernelcache/prelinkedkernel!
Works in 10.7+
PrelinkToKernel is powered by the Pike R. Alpha's LZVN.
Pike good luck and come back soon!