Just a thought- tried bot colors right?
Anyway, yeah a few.
The design isn't all that complicated for it. If you really wanted one, money aside, you could custom order the mount made from a fab shop. Just bring them the bike (with seat/bucket off), and show them a picture of the mount- they'll be able to recreate it in a hour or two off that if they rush it. You'd be surprised how many small shops there are around you that'd do it. The seat part is "easy" in that there's a shop for that too that makes custom seats...mostly is for people customizing their Harley, or making a seat on a bike from the 70's actually comfortable to sit on, but they'd make a clone of the buddy seat too I'd imagine.
If you can weld, I'd make the mount yourself. Seriously, just get some steel tubing and a tap set if you don't own one already. Don't have to make it all pretty, but could make something that'd work. If that's too much, could just get some steel plates to stack up and drill the appropriate holes into. The problem would still be getting the seat, but if you make the mount your self, you could adapt whatever rear seat you want to it.
I'd sell mine, but, it's currently my only 2 seater that's road legal. Hmmm, if I ever switch out the Kymco for somthing else- I'll take mine off and send it to you, but I imagine you'll find something else by then.