I've seen the USB Wi-Fi Connector at Best Buy this past Christmas season, which is weird because I thought it was online-only.
Nintendo of Canada decided that, for this and Electroplankton, it would be a better idea if they were available in certain retailers rather than only online like NOA was doing. A good decision!
I think that there should be a coupon for a USB adapter included with the Rev. 50% off or something. That way, whoever has one already won't get another one, and if you don't have one, you can get it cheap.