User Mode Linux experts wanted (alive)

[wildhorse]

If you have experience with User Mode Linux, maybe you can help me a bit.

I asked before in a different forum about a Userland Gentoo/Alpha solution, but so far I am not much closer to what I want.
https://forums.gentoo.org/viewtopic-p-5215356.html

The most important issue here is that my host operating system is POSIX and DII COE compliant, but it is not a Unix, and certainly not a Linux system. My first question to the experts is, how much does User Mode Linux rely on Linux-compatibility of the host system? How much does the UML kernel depend on a Linux host?

Compiling and linking the kernel will be fun enough, but before I begin with this adventure, I like to know in advance what else I might encounter and whether somebody has tried something similar, let's say on a Solaris system, or MS Window.

For me it would be useful to have a Gentoo system running on the same machine, but it has to be an application running on the host system. Virtualization, emulation and dual-boot are no option for me.

[wildhorse]

No User Mode Linux expert here?