Best reference for all the Pershing developmental versions is the Hunnicutt Pershing book (either edition--I have the reprint). There wasn't a Super Pershing with engineer attachments--it was simply a cleaned up version of the prototype that went to Europe. They were able to balance the long gun tube internally so the big spring housings on the turret roof of the pilot model were eliminated. 25 were built for evaluation purposes in the summer of 1945. The assault version was a standard Pershing with thicker armor castings, and a batch of 25 were also produced.
The experimental CEV prototype I mentioned was built in the mid 1950's on an M47 Patton. Featured a crane on the turret, a 165mm howitzer main armament and a dozer. It was successful, but by then the M47 was being phased out, so the principles were applied to an M60A1 to produce the M728. See Hunnicutt's Patton book for details.