Thanks for the welcome, and sorry for for the way I jumbled things up. I did mention this question has been making me crazy.
What I said was confusing - I would prefer to cut directly from Illustrator on the Mac, but unless I get a higher-end cutter that doesn't seem likely to happen. And yes, there's the option of running Windows in a virtual machine and switching programs -- which is only a difference in degree from switching between Mac apps to cut.
I had been looking at the SC2, but US Cutters' own buying guide says the SC series is "PC Only" and "Not compatible with the MAC OS." I could find references to the original SC working with the Mac, but not the SC2 - maybe I just missed it... (Edit: For example, missed this one right in the forum listing.) And I saw support for the SC listed in the description for SCALP, but given US Cutter's description you would want to see the SC2 listed explicitly there or somewhere. Especially since it also lists the MH series, where the MK2 units will work on the PC but not the Mac...
So the point of this, aside from venting the built-up frustration of the search, was just to see if anybody had actually seen Easy Cut Studio on OSX driving a RedSail cutter. Vendor claims are nice, but it's better to hear that it's actually working for somebody in the real world.