we would like to put our 4 year old basset bitch to a dog basset. is there a list of basset stud dogs anywhere? also, is 4 too old for her first litter?

By the time you have done your research about finding a SUITABLE basset stud and completed any breed relevant health tests yes your bitch will be too old.
It is not just about finding a male of the same breed but of finding a compatible male which will produce pups as near to breed standard as possible.
Archer

Hi , the ethics of the Basset hound club advises to mate your bitch for the first time at the age of two and last litter by the age of six. By the age of four the pelvic bones are set and welping could be a big problem. If you would like further info on breeding bassets, or joining the basset hound club . Please contact me at chrizbee@scoobydoobry.plus.com