If your goal is to create a leveling system there are reasons to use the same jack motors all the way around. That said if you want to try and create your own you could try to purchase the rear jacks that are part of the Lippert electric Ground Control system. These jacks operate much faster than the standard front landing legs on most trailers so it would be a problem when leveling side to side. This is why it is important that the legs all work at the same speed.
Good luck in your search.
Steve