I purchased a cable operated swivel boom from Northern Tool Company and replaced the hand crank winch with a 12 volt one. I mounted it just left of center of where the nose of my sled would be on the left half of the deck. The boom extends an additional 2 feet. I can pull up to the left side of the pickup and winch the snowbike up and swing it onto the deck. I had to reinforce the deck where I mounted the base of the boom to it, but it seems to work fairly well. Sorry, but I can't find any pictures. If I do I will post them.
I got the idea from a set up that had this same type of swivel boom mounted to the 2" receiver of the pickup. The problem I saw was that if you wanted to use the ramp to load or unload a sled you would have to remove the boom from the receiver.
An electric winch at the front of the deck with a wheel kit might be an idea. I'm just concerned about loosing my footing while walking the snowbike down the ramp when unloading. Could be quite a tumble.