I don't know of any units set up with a hyd motor & compressor in one unit but I'm sure they are out there. You could make your own very easily though. You won't need a belt drive, you could close couple the hyd motor to the compressor pump. This will make it very easy to find a place to mount the unit. You will need to know the hp requirement of your compressor pump plus the gpm@pressure of your hyd pump to order the hyd motor of the correct rpm and hp. The hyd motor to do this will be way under $100. I think you could come up with a great high output homemade air system for under $300 complete with tank, hoses and control valve. This wouldn't include your pto drive and hyd pump. I excel in this type set ups, if you need some advice please PM