I've been a big fan of tilt/shift lenses for years, having had an array of the Canon SLR T/S products. One of the negatives of moving to the Sony a7r series was a lack of such for that platform. However, I'm happy to report that the old Canon FD 35mm T/S works great on it via one of the standard adapters. Of all the Canon T/S lenses, the old 35mm FD was my favorite; so I'm a happy camper.
I might add -- and this is relevant to all of these optics -- that one "cost" of the wider image diameter that is needed for these T/S optics is a lower resolution. You don't get something for nothing. That said, the good news is that the Topaz AI Gigapixel software takes care of that problem nicely.
Paul
www.PaulRoark.com