So first, my sympathies, and thanks for posting what you found so far.
My CPU: amd64 (in case that matters)
From my perspective it seems that:
The old source for sheepshaver (May 2006 or so) are somehow too old for Karmic, likely due to changes in gcc or other build tools/libraries. Seems a futile exercise to use that in the long run.
The new source should be a better starting point, but CVS was offline yesterday.
Either seems to need hacking to be used on Ubuntu, I guess they (and Debian I suppose) do many things differently from how SheepShaver expects them to be to build. I noted the original author made it on Mandriva (ex-Mandrake).
And yours is the first mention of Karmic in this forum since I joined yesterday, there seem to be few Linux posts and even fewer Ubuntu ones.
I want to get this working, so I'll keep at it whenever I see some fix for a 'showstopper' like a failure in ./configure or make.
P.S. my username here and on the ubuntuforums is the same, in case you want to see what threads I read or wrote replies to there.