With the constant evolution, if you will, of the 1L bike motor technology, looks like there is a new HP leader in Production 1000cc motorcycles.
The MV Agusta F41000r 312 makes 183HP at 12,400rpm according to the June2007 Cycle World that I got in the mail today.
This isn't a bike you are likely to see in the salvage yard, or a motor you'll find on ebay. But the bike is expected to retail in the $25K range. Get out your checkbooks and do it quickly, only 150 units expected to be produced.