Has anyone attached kayaks to the rear ladder?

Ron, if that's your concern, and background, and you've access to friends with fabrication skills, I'd be building a hitch-mounted vertical rack out of 6063 or 7075 aluminum tube along the idea of that shown above.

By the time you go to the time and effort of modding the ladder you could have the whole rack done.

The other advantage, IMHO, of using a hitch-mounted rack is that the kayaks end up on the centerline of the M/H instead of off to one side as the ladder usually is.