I am one of BRAT's Basenji mix coordinators. Most of the Basenji mixes I come across are probably not that Basenji, but some of them definitely are. Of course most are not from known parentage. This dog is currently on the BRAT adoption site, I'd say that she's a fairly high mix: http://www.basenjirescue.org/DOGS-MIXES/MS/MS-Bebe.asp
-Joanne
I would also look on Petharbor and Adopt-A-Pet. It can be difficult to find one under 1 year of age. You might have to go farther in your search or perhaps raise the age to 2 years.