The november issue of the free Motocrossdigital magazine ( download it at http://www.motocrossdigital.com ) has a feature about this seasons factory mx bikes including the Aprilia MXV. Very interesting read and I advise you to download the magazine and read it for yourself. Some interesting news. The bike has 10% more power than its japanese counterparts,it currently has a honda swingwarm,it weighs 108kg's. The new big bang configuration seems to be very succesful. The reporter found Chiodi's bike the most powerful bike he has ever ridden but it's too heavy in the front. The report says that the production bike will be there at the end 2008/beginning 2009. For 2008 their will be a lot of changes including changes to the engine block,frame and reducing of overall weight. Also the old style swingarm is coming back. In short a complete overhaul of the MXV.
Also Aprilia has been working on a 250 MX bike for a year now. No details about that one yet. But it's real.