Chris you are so correct referring to earlier engine designs, even the wonderful Henderson 4 was 'in line' along the frame albeit air cooled, however Motoczysz have developed their own 21st Century high revving engine for MotoGP, a very different performance arena, btw I love all motorcycles including the Henderson 4 I spotted at Ramsey this year:

http://www.deejay51.com/tt2010_ramsey_sprint.htm

I suppose my reason for going on about Motoczysz is a 'breath of fresh air' if you will, given the never ending minor updates to UJM4's. I've been on about the need for VARIETY for some years now, suffice to say the Superbike, Supersport, Senior and Sidecar 'engines' as a whole are basically all from the same mold with varying 'go fast' embellishments. We do need to witness change...