We first bought into the Zebra platform just last year. During our evaluation, I was also looking at some of the Express equipment, because size-wise we're right on the line between the two options. I'd swear that at one point my RFS4010 had somehow adopted the AP7522E I was playing with.
Unfortunately, I haven't been able to repeat that. I still have that Express AP, but I have to run it in a part of campus that's not yet updated to our new platform.