Did you run MultiBeast as part of the UniBeast installation? If so, MultiBeast installs Chimera if you choose EasyBeast or UserDSDT (or DSDT-Free Installation). However, I'll double check with MacMan.I stand corrected.
What I don't understand then, is, after a format and a fresh Unibeast install, with my mobo bios set to boot from the HDD and ignore the USB, the first restart finds Chimera and will boot from the HDD. And there is a boot file in the root directory.