@T-Jones - Go to www.basenji.org and then to the link for find a puppy, you can then search by state for breeders. Breeders listed here are members of the Basenji Club of America parent club. Breeders here do health test with the results of those test on a public website for anyone to check out (which you should do, just don't take someone's word for it). At the very least, DNA testing for Fanconi and PRA should be done. Here is a link of a fully tested Basenji (mine) and all the tests that have been completed as an example.
Note as an FYI, usually same sex is not a good idea, most breeders recommend opposite sexs. And littermates are not always a good idea, they have been competing with each other since birth for food, attention, play time, etc.... this usually continues into adulthood (competing). One last comment, 99% of responsible breeders bred for a well rounded Basenji, one that can compete in the Show ring, Lure Field, Obedience, etc in addition to breeding healthy great companion Basenjis.
It's usually easier to add a pup later, after your first has some basic training, manners, and is an adult or approaching adulthood. Teaching two pups together can be challenging, and there is no role model! One Basenji pup is a challenge. Two? Maybe if you have a lot of time on your hands! (although they may tend to wear each other out).
A lot of people get 2 pups at once, but different litters, opposite sex. I personally prefer one at a time so they bond more with humans than each other. Getting another the next season gives time to get the first settled. Of course, then you have another round of house breaking etc. A lot depends on your own experience with the breed. Good luck ... the link Pat gave you is your best bet for well bred puppies. :)