Now that FreeBSD has EFI support such as for booting from USB storage, you can partially boot a MacBook from it if you hold down Option while powering on or rebooting. The problem is the FreeBSD boot loader does not switch the Mac's screen from graphical to text mode so you can see anything. It silently books in the background. A while ago Rafael Espíndola emailed patches in this thread: http://www.mail-archive.com/freebsd-current@freebsd.org/msg155044.html I tried it and was successful at getting the boot loader to switch to text mode so I could see what was going on. The kernel stopped printing to the screen shortly after it started booting, only printing EFI framebuffer information then stopping. That is probably a different issue. I was able to get a serial login by modifying USB media to spawn a terminal on a USB serial adapter, so I could tell the system was actually running silently (also based on disk activity).
This seems completely solved as of 10.1-BETA3 (and head) on my "late 2011" macbookpro. It even has working kernel console output and use after the boot loader. Thanks!