I just had a look through the custom maps of the Quake3 mappack, looking for suitable 1on1 maps.
Like for the 2on2 maps I was looking for maps that perform somewhat OK, have the appropiate size and aren't too tiny, because the big Nexuiz models need some space to maneuver nicely and to be able to use the movement tricks.
The only map I could find interesting, fulfilling these criterias, was dm_quimera. I'd like you to test that map and play a couple of 1vs1 matches on it and then vote whether you like to see it in the mappool.
The map can be played on the planetnexuiz.de:26500 server, and probably also on other 1on1 ladder servers, you'll have to check it out via chmap dm_quimera on these servers.
The poll will be open for 2 weeks.