There's a directory of stations with AM stereo offerings on the web (one of a few) in our station FAQ page.
As far as receivers, they're on the secondary market everywhere! Carvin TX-11A's or the Realistic TM-152 for "old school" receivers for your home. In the car, the "Directed" brand HD radio adapter (add on with modulator and RCA cables) will add CQUAM to your auto, and many vehciles from the Chrysler family up through around 2003 had it built in to their RAZ model radios. We broadcast it for fun, and for the public interest it creates, plus, it raises awareness on our stream of how GOOD AM can sound in an era where many broadcasters are wasting their AM signals and not maintaining their "physical plants" for them...just letting 'em limp by.
Since WION was AM only for years, (and when we bought it) we wanted the BEST sound we could put out through our towers...and I believe we've achieved it!
Oh, and as Scott here said, some HD radios of today do CQUAM. The Radio Shack "Accurian" tabletop HD is one that is reported to do it. For techies, you can even get a cquam board and install it in your favorite home stereo, the Meduci company sells those on their site, and often on Ebay.