I am also a great fan of Steely Dan, but I think they are unique.
They are not a "typical" rock band as they care little for on stage postering or cultivating their image.
Their lyrics are clever and witty and the music is a great mix of rock and jazz.
They also spend longer than the average band producing their music, choosing the best musicians, and getting the right sound.
If I look at some of the bands listed on the "last.FM" site who they say are similar I find so many of them are nothing like Steely Dan.
http://www.last.fm/mu...y+Dan/+similar?page=1
Good luck in your search.