low cash is an air conditioning compressor hack. Seen this done of TJ54's little red, but haven't seen him around much. He might still be lurking.
Essentially, just use a a/c unit with some odd bits of pluming and a blow off and you've got a solution. All be it a slow solution, but cheaper than off the shelf.
I'm not sure I'd refer to an A/C pump converted to on board air as low cash or hack.
I installed a junkyard york A/C compressor on my last Jeep (Kilby mount) and would run it against ANY of the portable air units.
Re-seat a popped bead - no problem
100% duty cycle - no problem
Run a 1/2 drive impact - no problem.
In fact, my next Jeep will have another York compressor as an air source, (although next time, I'll get the entire kit from Kilby instead of piecing it together. The bits and pieces will nickel & dime you the death)
Heres a kit for the JK, it ain't cheap but you could buy only what you need instead of the whole package.
http://www.kilbyenterprises.com/KE-2200-K.htmVince