I use a 3 HP long-shaft on my DS, which I mounted on a bracket. The bracket was made of a piece of mast - about 8 inches long with an aluminum plate at each end. One end is bolted to the transom, the other had a piece of wood attached to it to become the base for the motor. It works well.
I agree that motors are a nuisance, but they sure are handy in sudden squalls or dead air. Being a purist is nice, but not always practical (or safe).
A long-shaft model is best. I tried a short-shaft, but when going forward to pick up my mooring bouy, the cooling water intake came out of the water. Not good for a motor.
Terry Sylvia (tsylvia-at-capecod.net)