It looks like there could be some trouble for the 450 crowd soon.can-am ds450 is looking serious with a aircraft style frame(not welded) assembly and engine designed for power and lite weight.(not yet revealed) brp has an extensive v twin line up as does aprilia.it sould be interesting.
http://can-amds450.com/
and the aprilia is not yet a quad engine but doing very well with 60 hp stock in europe
Click to view attachment