> It appears that it is not supported in 1.2 or 1.2.1, but
> I've seen someone's dmesg dump in the mailing list archives
> which indicates support is available somewhere.
>

Yes, it is in current, but not in 1.2 or 1.2.1

> If it is in current, how difficult would it be to merge
> the specific changes into 1.2 to provide support?
> 

It is not really difficult, but also not straightforward since there have
been a number of small changes in the relevant files.

Look for `sys/arch/sparc/dev/lebuffer.*' and corresponding entries in
files.sparc & GENERIC. Then merge in the attach code in dev/if_le.c.

-pk