The person you want to talk to about lapping tables is Mitch Saunders at Saunders Machinery Company. Lapping tables are his specialty, buys and sells then. I don't want to post his email on a public forum, so if you shoot me an email (my adress can be found on the 'Contact' page of Hanson Hydraulics Ltd. home page:
http://hansonhydraulics.com ) I will reply with his email adress.
I have a few 22 series variable pumps (manual controllers) and 22 series fixed motors. I also have a 27 series fixed displacement motor. I'm in the process of building a second 'regen style' test bench, but it is a filler job and nowhere near completion. For information on regen style test benches, check out Machinery Service and Design
http://www.ms-d.com/ Basically you have a variable pump driven by either an engine or electric motor, which then drives your drive motor on the test bench (this can be fixed or variable, your choice) which in turns drives the pump your testing. Instead of the output flow from the pump you are testing going to a relief valve and wasting energy, it drives a regen motor (with rectifier block) which drives the regen pump, also variable displacement, this output flow feeds back into the initial drive loop. The only power you need to supply for this regen style bench is to make up for the inefficiencies of each of the pumps and motors on the bench. Usually with a 50hp electric motor on a regen bench you can test a pump up to 150 HP.
When testing a motor, there are a couple of ways you can do it, the way I like if your building a single station test bench is to use a six way selector valve or quick connects so that you can directly drive the motor being tested from the pump attached to your prime mover. The motor being tested now spins the test benches drive motor as a pump (charge pressure supply required). The oil from this motor/pump then feeds your regen motor and the rest is as above.