I'm not sure how much "dry canyoneering" is available in Zion. Most of the stuff I'm aware of involves water. You could try bogley.com to see if they have any suggestions (an outdoor website mostly focused on canyoneering). I think you would have a better shot at a trip like that around Moab. It was some years ago, but I did a trip with Desert Highlights in Lomatium Canyon and it was pretty much dry (one place we took off our shoes). I don't think they offer that trip anymore, but if you are doing it independently you could look into that one.
Have you been to the southwest before (not sure if places you haven't mentioned you've already visited)? Is your itinerary set in stone? If you are a backpacker, I would strongly consider adding Coyote Gulch in Escalante (there are also some canyoneering trips in Escalante, but I think most involve water).
If you are staying around Zion and haven't been to Bryce, it's worth a day trip or an overnight stay.
If it's at all possible, I would try to squeeze in some time in Page. That's one of my favorite areas (especially if you are willing to get off the beaten path) - a lot of great things to explore and photograph there.
No matter what you choose you'll have a great trip - enjoy!