Unless you plan to run air tools, you don't really need a tank. I converted my stock (Sanden) a/c compressor into OBA and don't run a tank, primarily because I didn't want to hassle with the additional plumbing and I do a lot of rock-crawling and wasn't sure where to mount it.
And although the Sanden doesn't have as much flow as the York, it still does very well and you can find used ones for $50-75. I air up my 35s from 7-36 psi in < 2 minutes each with this setup. And the oil use is minimal; I've got a mist oiler that I installed 1 year ago and have not needed to replenish the reservoir.
2001 2.5L TJ, HPD30/D44 with dual OX and 4.88, full armor, X20-8 winch, 35" STTs on 15x8 black Cragar Soft 8s, 1" BL, 1" Brown Dog MM, 4.5" suspension w/ fully adjustable control arms and tie rod upgrade, OBA