If you were in southern England I could help you!

Try contacting a local office plant company as they may be able to help. I know nothing about the wholesale system in the US but I can just pick up the phone and order up to 1m specimens from Holland.

I expect it would cost $200+ though!

There's a shop in Chicago called Gethsemane that always has large specimen plant for sale and large Jades are often on display. Try there.