Well the bmw s1000rr has a top speed of 299 with a governor, as the zx14 and the busa. OK the BMW is the only litre bike but I don't think it is too hard to get an R1 to go over 300, hell I got my FZ up to 265 and that bike is only a 750.
Most modern litre bikes can easilly pass 300 kp/h. GP bikes most times are not geared for top end. IF you gear an R1 for top end without any other mods besides re-mapping (changing governor settings), 300 is no problem.
Any R1 owners want to chime in here. I have never owned a fuel injected bike, I don't know the tehnical details of what needs to be done. Although I'm certain it can be.
Look up the speed records at bonneville, you have 500cc normally aspirated bikes coming close to the 300 mark.
here is the link.
http://www.scta-bni.org/Bonneville/BNI_records.htm