> 1) Put the kernel below F0000000.  This will severly limit both the
	> size of the kernel and userspace.

	Can you give me a hint why?

Then the OBP would be entirely within kernel space.  The kernel
and userland would both have to reside below F0000000.  You may
be able to put the kernel heap and I/O areas above the PROM, but
that may require twiddling memory maps.

Eduardo