Now if they'd just release Duke Nukem 3D source, we'd be all set.
ftp://ftp.3drealms.com/source/rottsource.zip
I know that Icculus is hoping someone will port it, but a lot of people are busy. I don't know C++ yet, or else I would do it.
But anyhow, just thought I'd inform you all that it's out there.
Update: Looks like they're working on it already: http://cvs.icculus.org/horde/chora/cvs.php?rt=rott