Low Profile SAE Mounting Adapter?

[MToomey]

Good morning,
I'm not sure about the right place to ask this, but it's an SAE spec and it's part of a power transmission assembly, figured this might be a decent shot—Let me know if there is somewhere else that might have a better idea.

So:
I am designing a special hydraulic power unit for one-off kind of build my company is doing. I have a propane engine and a hydraulic pump that have been spec'd in by respective people in the company.
I have a splined hub to adapt from the engine to the pump spline, but the bell housing is an SAE A 4-bolt pattern while the pump has an SAE B 2-bolt mount. I don't know how much space we will have yet, so I would like to stay as compact as possible.
I am picturing a plate with a male SAE A pilot diameter on one side and a female SAE B pilot diameter, countersunk flat head screws holding the A pattern to the motor and two tapped holes for the B pattern to bolt up.

Does such a product exist or would I be better off drawing a part and paying a machine shop to make two of them?
Is this a situation in which it would be more proper to use a shaft coupler and standard adapter?

I would be happy to clarify anything if I have left some question marks behind!

 

[CWB1]

PTO adapters are commercially made by many companies. Engine and pump manufacturers usually have a plethora they’ll sell bc it enables sales, so I’d start by calling your suppliers for their pricing then check the aftermarket.

 

[MToomey]

PTO adapters are commercially made by many companies. Engine and pump manufacturers usually have a plethora they’ll sell bc it enables sales, so I’d start by calling your suppliers for their pricing then check the aftermarket.

I have seen plenty of machined castings, but I'm looking for essentially a 3/4" plate with a boss on one side.
Are those included in the plethora? Because I haven't found the correct search terms to find those.

I suppose I'm mostly asking does that exist or am I wasting my time searching for it.