Large diameter mouning rings?

[whoppo]

I'm looking for a set of rings to mount a 36mm diameter "object" to standard picatinny rails. There's tons of 30mm mounts around for cheap money, but the only thing I've found even close to large enough was a couple hundred dollars. Does anyone know where I might find such a thing (cheap) so I can complete my "secret project"? (I promise to post pics/videos if I can pull this off... er.. I mean bolt this on)

Thanks!
Ron