You might try the archives on this subject... because there has been a lot of discussion over the years. Always a somewhat controversial subject for smaller boats, but converting a 29 footer would certainly have less negativity. What are your reasons for the conversion?
The thing about wheels are, they take up a lot of room in the cockpit, the autopilots are way more expensive, and there's not as much "feel" when steering. It also sticks the driver at the very back... because most folks have a tendency to stand behind the wheel and drive the boat like a truck... .
If I were converting I'd want a large, destroyer type wheel so I could still sit on the rail and see my telltales... but the benches in the already narrow cockpit restrict it... so you'd have to have a pretty small wheel and that means less feel and restrictions to steering positions......and.. a small wheel doesn't look as cool as a big one.
An adequate tiller pilot can be installed for under $500. A low end wheel pilot will be twice that, or more.. if you get the good one.
The plus side is that on your size boat, it might increase the resale value. The cockpit may be large enough... width and depth. And it may not affect the single handing convenience offered by a tiller.
Cost wise... I don't specifically know, others will contribute there. I'm thinking in the $2-3k range. Edson is the best known manufacturer of wheel steering systems.
http://www.edsonmarine.com/support/wheel_conversion/