Not heard of one.
I own an H37C and know many of the other owners. I have been following this board, especially the 37-cutter, since 1998. I have never heard of electric shifting for our boats.But I also believe it would not be difficult to install. Those kind of solenoids are readily available, just a matter of some wiring and a mount. Some searching with Google would probably find a kit. My feeling though is that it is first and foremost a sailboat. And the gearshift lever on the transmission is easily reached. Do you really trust electrical more than mechanical? I am just thinking out loud here. You might have a very good point. Let's see what others have to say on the subject.