Support for MMU less systems

Hello,
I google'd around for information on efforts to port NetBSD to work on a mmuless
system, and found some mails. I guess there has been no effort except
for a brief
communication of issues/change involved to the source.
Can anybody post -
a) If there have been any efforts?
b) If there are no efforts currently, then when would be a good time
to start such an
    effort?
    Can we list down the issues in detail?

Best Regards,
GPN