Another vote for Cherryh's
Chanur series. You might like her "Company War" books, too-- they aren't a series, per se, but are set in the same universe and share some characters, as well as a common history. Try
Rimrunners. It isn't the first in the sequence (that would be
Heavy Time according to the author) but it is very readable and has plenty of action. (I had some other books to recommend, e.g. Card's
Ender series, but I don't see them as ebooks at my usual sources.
)