Servonaut BMA is very similar to what Leimbach offers.
http://www.tematik.de/servonaut/Prod...r/BMA/bma.html
I have few of those in use. It works nice with Servonaut SMT soundmodule: when the hd-pump starts it will increase the engine revolutions like in the real thing. It will also make the engine sound like it´s under a load when the hd-cylinders move.