Brainstorming earlier today I think I have found a way to use
an linux kernel for the boot loader and to implement pcbios
compatibility without too much cost. The idea is to use
a uclinux kernel. And implement a ``user space'' aplication
that is a user space shim that makes kernel calls.
There are a few nasty details to work out like how to handle
services that are expected to work in vm86 mode. But I'm
not certain I care.
After I come back from my christmas vacation I am going to have to try
it and see how will it will actually work.