A friend of mine had an Adock and Shipley 1ES with a Bridgeport M head, which is an interesting package in a small footprint. The factory ones had a power socket for the head on the body. However the Bridgeport M head isn't particularly heavy duty . I've seen them with J heads as well and once grafted a Bridgeport J head onto an Elliot U0 mill. The downside is that the absence of any mechanism to move the ram made it a real pain to move the head in and out.
Charles
Charles