I know many modern bikes will rev to about 14000rpm (600's)
The Honda 250cc 6 cylinder racers revved to 18000rpm (I can't find whether these were desmo or not - sorry)
It doesn't really answer your question, but gives a clue where to look for high revving motors with valve springs
P.S. - this is an amazing read for you technophiles...........
http://www.motorcyclistonline.com/featu ... index.html
A snippet:
Other details emerged that showed the remarkable lengths to which the Six's design team had gone to reduce the mass of moving components. JPX was astounded to discover three different types of con-rods in each engine, with progressively larger big-end bearings for the rods nearer the center, where loadings are higher. Even 40 years ago the benefit of such a strategy was well-known, but no one else bothered to take advantage of it. Any other manufacturer would have made six identical rods, each able to cope with the highest possible loading. But Honda's obsessive desire to have no component heavier than it need be caused the engineers to tailor each pair precisely for their function.
Unless I missed it - I still don't see a reference to valve gear, although it refers to camshafts am I right in thinking I shouldn't assume it's not a desmo?