Is anyone aware of a technology like "iPilot" for a transom mounted portable TM? If not , does anyone have a DYI that they have developed?

No. For liability if nothing else. Spotlock would turn the boat with the back into the wind and waves leading to sinking of a boat in rough water. With remotes to control the TM I am not sure why you'd need it on the transom.

Actually, I fish a lot of smaller fisheries (under 300 acres) in a pond prowler type "tub". I use a transom mount TM and flip the head around, mount it on the front and off I go. As I fish alone it would be nice on a windy day to not be pitching out two anchors at each spot.

Having been way north and experienced some of the walleye, smallie, musky...fishing so many of those yankees do and the style fishing so many of them do with their big high sided aluminum v-hulls I would think there would be a big market for transom mounted trollers that could spot lock, follow contours..... Waves? Heck they all “back troll” in 30mph winds with splash guards across the back of their already tall transoms to keep from swamping their boats!

If you are fishing out of something like a bass buster and want it up front, I'd look at a powerdrive or a terrova. You could make an adaptor plate that mounted it and you can use your hand to depress the lever and lower it into the water. That would seem pretty easy to do and use a quick release plate when travelling. Wouldn\t need the foot pedal, just the remote. That would be the easiest way that I can think of. The motor that turns the head is at the base of the mount. I'm sure you could probably find a way to alter that and make a mount for a transom if you try.