Campagnolo Veloce compatibility - small rear derailleur with larger (29 or larger) cassette?

I don't have Campagnolo's specifications in front of me, but I suspect they will say that this combination is not compatible. (NB: see comments, I may be wrong.) However, I used to have a Record 10s rear derailleur from the mid 2000s. It did work acceptably with a 13-29 cassette. I recall several people discussing this or similar combinations on the Paceline forum and other forums. In other words, Campagnolo's chain wrap and largest cog specifications are often conservative, as are Shimano's. It may not work acceptable with all bicycles, but as long as you can adjust the B-tension screw enough, you should be able to make it work. I believe you can also get 10s 12-27 cassettes, although these may be under the Centaur or Potenza models.

All the Campagnolo deraileurs of that era were rated for 29t. If you want to try 32, you will need to find a mid Potenza derailleur (which despite being branded 11sp, will work properly with your 10sp shifters) and use an aftermarket 10sp cassette that provides the 32t sprocket.