Tilt Shift is one of my favorite features of a large format camera. When I switched to digital, I, too, rented Canon's TS lenses to see if I could be happy in 35mm, trying to duplicate my large format pleasure. My effort failed.
I found it virtually impossible to guarantee a center of focus on Canon's TS lenses, especially in lower light situations. My inability to secure focus threw me into a pit of 35mm TS despair. For me, looking through the viewfinder of a 35mm camera is a joke when compared to checking focus on any large format camera. Accurate placement of focus is crucial to my work.
Even if it's possible, I imagine creating an auto-focus feature on TS lenses would be a very expensive accomplishment. Given the limited market for TS lenses, I don't anticipate AF ever coming into play. I'm not an exclusive AF shooter, either, but given my eyeglass prescription, I find being able to compare AF versus Manual in the viewfinder extremely helpful in achieving the desired focal plane.
I've never tried to create the TS effect in Photoshop (fake gimmick is not my style) but this thread has inspired me to take a look at the possibilities. Maybe with some careful tinkering, I can develop a technique that will endear me to 35mm even more. Thank you all.