Here is a very biased suggestion..
Tarptent Scarp 1/2
http://www.tarptent.com/scarp1rev.html
(the 2010 Scarp 2 is the same but wider...)
That is actually an integral pitch (inner and fly together) but you can detach the inner ("tent') if you like.
You could also consider the Double Rainbow (dry set-up) with the optional liner if you are worried about drips from condensation in a single wall shelter.
Here is a very quick video of the DR sans liner. I will do a better video once I get the liner.
http://www.youtube.com/watch?v=Gv8Mxbpc1ac&feature=channel
This was done very quickly , so ignore the slightly crappy pitch.
Franco