You may remember Makaqu Quake Engine for Dreamcast & Windows. Probably the best Quake engine for Dreamcast.
It is still available here:
Its creator want to update it and it depends on your interest so if you really want it - show you support here http://dcemulation.org/phpBB/viewtopic. ... 1#p1050631
Not registered - there is his twitter let him know that way.