Are you strictly looking for a rescue or are you open to getting an adult from a breeder? Breeders occasionally have adults available and there are a lot of great ones in OH/Midwest.
Sue Kite/Jeff Gillespie of Klassic Basenjis
Becky Blansett of Epic Basenjis
Tracy Leonard of Select Basenjis
Tim Huff of Victory Basenjis
Are all breeders I know in Ohio.
My dogs come from Tad Brooks (KY) and Jan Kahl (MO). Tad is about 5 hours away from me (I'm from Cleveland) and I know he has adults available from time to time :). I'm very happy with my boys from him!