You'd be only the second person to do it, the first being the writer of the original startup code.
NetBSD, Linux-68k, A/UX all use the Mac OS to do the bootstrap. It's a nightmare unless you restrict yourself to a single class of machine.
The Class Macintosh OS is not a good example of a clean operating system design. It's just full of kludges, bodges, shoe-horns, dead-ends and twisty-little-passages-all-alike.