Wow, a lot of things and suggestions to respond to
Lets start from the beginning...
My suggestion for the cart/wheels would be to go around the rear bar, which would also possibly aid in the support of it. Hard to explain in a way, but having a curved semi circle with mounting points replacing the skids, and the wheels at the other end. The bars would loop around the rear handle, providing multiple features....a platform to support the rear when the bar is down, curved bars would provide basically a torsion suspension for moving the kayak, and would continue you mount out of the way. I will attempt to post a picture, after this thread...but for the most part, it could be constructed out of conduit....Light, sturdy, and able to bend with ease for construction.
I like your first comment of the ability to self recover from deep water. Trust me, this would be practiced over and over again. I prepare and consider everything before I take on something which could turn out to be dangerous....i.e. Fishing in a canyon with a 400ft depth, in between 100ft. canyon walls, and in the middle of the fall where the water is 50 degress....so yeah, it would be practiced in 10ft. water where the water is 75 degrees first
Thanks. I like your idea of the mounts to cradle the hull of the kayak as well. Maybe I'll try to incorporate that in to a design.
As for the downrigger....that was just one place I was thinking of mounting it. Of course, with the star boards and everything else, there are several other possibilities, which also include not having a downrigger at all.
Thanks for the comments....I'm sure 95% of all failure is due to operator error. I just saw the pictures of the seat extension, which was different than what I thought it would be...however, I think for a person of my size at the time...the lower I can get to the water, the better
Last but not least, atavuss:
Sweet trailer!!! Love the idea and not only that, it would enable me to tow it with my XJ Cherokee to the lake, or with my Polaris RZR (actually my paps) to tow it to high mountain lakes. I'll have to look in to that. I think I saw one a while back, but it was more like a utility box trailer...same concept, just had some hatches on the side.