I've thought about adding three point pins to my existing set of SSQA forks, but haven't done it yet. I think that would be the easiest way to go. I've also considered just buying a set for the three point, so I could carry a pallet on the front and one on the back at the same time. I hear Agri-supply has them for a pretty good price. I've also considered a three point forklift mast. There's a used one available locally for around $500. That seems like a good option since you could put stuff up high, but I suppose you lose some lift capacity due to the weight of the unit.
Good luck with your search, and let us know what you figure out.