Brian, there was never a rear mower for the Cub Cadet. There have been some homemade rear mowers. I will have to dig up some photos of one made from a 38” timed deck. I think most of the rear PTOs were used to power hay bale elevators.
There really were NO rear pto powered attachments or implements made by IHC or MTD or CCC for that pto. That pto was actually a spin-off of the rear PTO from the FARMALL CUB and Cub Lo-Boy. The Cub Cadet rear rototiller used the front pto and a long L-O-N-G belt to provide power the the rear of the tractor. Can't remember who it was but somebody built a modified 38 inch timed 2 blade deck off an Original to attach to the CUB pto and work properly. I saw it at a RPRU but didn't pay a lot of attention to the details.
Now on the Super garden tractors, there was a finer spline 15/16 inch internal spline pto available, electric clutch, 2000 rpm, and think it was DANCO who made a 42" cat O 3 pt hitch rotary cutter, and a 42" rototiller also cat O, And if you live near Osh Kosh, Wi. you have a Cat O 3-pt mounted yard sprayer with a pto powered pump from that rear mounted pto. There were several companies that made attachments for the pto on the Super's, several tractor brands had rear pto's but they all struggled to come up with a standard speed and direction of rotation.
That looks pretty awesome. Seems like they were going for a miniature tractor look with a narrow front end, large narrow rears and a conventional looking pto shaft. Also, that rear section with the IH sticker, is that just a cover or is it a lift to fit the rear tires?
Denny is correct about PTO output shaft on a gear drive Cub Cadet being a descendant option from the Farmall Cub since the CC transmission was adapted to the Cub. The design is not exactly the same but similar. The rotation direction of the Cub Cadet PTO was the opposite a Cub and any other standard tractor. However, there was the bolt on PTO adaptor/reverser by Danco, I think, that attached to the back of the transmission housing/input shaft and provided a 540 RPM PTO output shaft w/correct rotation direction for a PTO shaft driven attachment. The most frequent use for this attachment was auger duty during harvest to transfer grain from the grain truck and into the grain bin. Typical augers were only 6 or 8" diameter back then and 10-12 hp engine could run one just fine.