FastCap has solved the problem by designing a chisel with a multitool-style handle that folds together to protect the blade. In use, the chisel behaves like any other I've tried. It is adequately sharp right out of the package, and the two solidly mounted halves of the locking nylon handle are sturdily attached to the steel blade and can take a hammer blow with no ill effect.
The Pocket Chisel is available with 1/4-in., 1/2-in., 3/4-in., and 1-in. blades; each size has a different-color handle for easy identification.