I found a 135mm T mount lens on ebay for $30 and figured for the money I'd give it a shot. It screwed directly onto my Astronomik filter tray, and my SXV-H9 screws directly into the filter tray. I gave it a quick test on a stationary tripod and found I could focus stars easily, so the lens/ccd distance was good. The image above is my first imaging attempt. Taken under a blazing Moon, the sky background was about 10000 counts/minute in L so its very noisy and I had trouble flat fielding the sky. However I was real happy with the way the stars looked. I took 25 exposures of 30 seconds each unguided on my GPDX, and because of alignment problems there was some star trailing.
I get 9.76 arc-seconds/pixels and about 3.7 x 2.8 degrees FOV.
I had read that some T mount lenses had a greater rear lens to camera plane distance than others so I was hoping I could fit a filter tray/wheel in the optical path. It works!
Look for a Vivitar or Soligar T4 lens and it will probably be like the one I found. This site has alot of info.