If you go into the "About" menu of the Central, there are a couple of models listed on that screen.
Technically, any adapter that uses the exact same chipset as those models will also work. However, during alpha testing, it was discovered that one of those models changed chipsets mid-production-run. (I had one of the later ones and it didn't work, whereas the one back in Cambridge did work.) They fixed the software to support both chipsets, but my point is that sometimes even the model number of a USB adapter isn't always a proper indicator.
In any case, if you look up the info on the web about those two adapters and find out what chipsets are contained within, then search on those chipsets, you might get a decent list of models. I haven't tried doing this yet, I'd be curious what you come up with.
