Hi,
There's a few options with the B2650 for rear remote hydraulics.
If you have a backhoe you can go the cheaper route and make your own setup using the power beyond and there's a drain hose that can be tied into for return to tank.
Then there's the kit from Kubota that is basically just that but has an adapter plate for power beyond that goes where the hydraulic valves would normally mount, and ties into the same return hose for a drain.
Then, if you don't mind a bit of work, you can do what I did and use the factory setup for a B2630 and have the two levers on the right fender where the power outlet/storage pocket is. You will have to cut about 2x2" section out of the panel that braces the fenders to allow the levers to pass through. And you'll have to figure out a spot to mount the remotes, in my case I left them hanging until the weather is nicer, I'm going to mount the quick connect blocks on the inside of the rops just above the fender, which will require some different hoses be made. If you don't have a backhoe you should be able to get away with the hoses in the kit.
Good luck and figure out how many valves you may need before deciding.
Kyle