It can be done, but overall cost would be too much for any boat manfacture to include it. The R&D would not be worth it to the bigger companies. There is a boat in the custom world that is new with a hydraulic panel that opens from the front of the bow to the beach for easy access on and off the boat. http://www.tridentboats.com/
Sounds like a good idea for small kids, edlerly , fat people, and dogs, but I just don't see it as something the companies would ever do. I expect more of the companies going to 2 speed transmitions first.