Small update:
I picked up the big items for the sand blasting setup. It won't be assembled and up and running for another 2 weeks probably. I have to have an electrician come by and sort out the power. Being in a rented commercial building, I can't do the work myself. I also have to get a foot pedal, pinch valve, and some other plumbing/filters/drains so the setup can be bolted to the floor.
After doing quite a bit of research, I didn't really find anything on craigslist that seemed worth the effort of draging it over to the shop to just have it fail. A lot of 15-20 year old stuff and a lot of people using big box 60 gal units still wanting $300 for them.
In the end, I got the IR SS3L3 compressor. It's a 3HP 60 gal single stage. I know it won't be great, and it wasn't cheap (almost double what HF's unit was), but I just don't feel like messing around with a failed compressor. The IR unit has overall good reviews. 43 4-5 star reviews on Northern Tool. Most talking about the purchase after owning for 18+ months. We also bought directly from IR which is only 15 minutes from the shop in an industrial center with 3 of our distributors, so getting parts/repairs will be more convenient. As for the big box stores, the HF unit had mixed reviews. The Kobalt unit is discontinued. The HD unit is also discontinued(probably what I was going to get because of the 4 year warranty). The Campbell Hausfeld unit had mixed reviews. More than one person complaining about failed compressors.
Discussion made. In a few weeks I might do a final update and show some other interesting products/projects I might think about offering. I'm thinking about getting some intake gasket material and cutting them on the laser or the CNC. I can also make some pretty decent looking tags to go on manifolds/intercoolers, that are a little different than the current ones available.