APS-C is not the preferred format for tilt shift functionality. It's just too small to mate all that well with existing lenses.
You can check out the
Arax products. These are only 35mm in focal length, which is too long for most architectural purposes. I once owned a Pentax 28mm shift manual lens and other ones come up on the Marketplace now and then. But shift is not tilt shift of course.
If you are serious about using tilt shift lenses, consider using either Canon or Nikon systems. The Canon 17mm is supposed to be outstanding. Even my Canon 24mm TSE on my 7D works out OK enough using LiveView, as I'm learning to use stitched images for landscape capture.
M