As you may be aware, Aprilia brought a semi-street-legal (headlights, tail lights, but incorrect wiring harness and off-road use only title) RS125 to the U.S. for 2009, however Europe and the rest of the world has been enjoying 125's for years. Offered for sale in Redwood City, California is a titled and plated street legal 2006 European market Aprilia RS125. This example shows only 305 original miles and looks to be in excellent condition. The asking price of $8500 may be a bit high as supposedly plated '09 RS125's have been advertised at around $6-6.5k ($5449 MSRP for the non-street legal version). However, this is a legitimately plated bike and quite possibly the only plated 2006 (there may be a couple more) in the U.S.; it comes with desirable performance accessories, spares, and all the original parts. The 2006MY is the first for the latest iteration of the RS125 that includes the 2009's. If seriously interested, money may talk and a sold price could be well under the asking, but don't expect it to be under the going price of the '09's. Is it sad that we lust over what is just an entry level bike in Europe? See the Craigslist ad here. And the hi-res Flickr photos here.
EDIT: Now advertised at $7900.