I just bought a rebuilt ISC from a company in Houston that basically just works with ISC's and ECU's from DSM cars. It wasn't the cheapest ($125), but they give a 1 year warranty and seem pretty trustworthy. I haven't installed the new ISC yet but would assume it works fine.
The website is www.ecmtogo.com or the phone number is 1-888-ECMTOGO if you want to check them out.
Price is $165 shipped now, sadly the other places I called didn't have any, so thats what I paid.