I know that this has been a 1st of April wind up but...
In Europe the BEARS racing (British,European and American Racing Series) reg's didn't allow 4V's+Desmo+watercooled+fuel injection, you could have 3 of the 4 but not all 4.
So a successfull Ducati racing outfit over here in the UK, Baines racing had a Desmoquatro motor modified to valve spring operation and finished either 1st or 2nd in the Europe wide Championships.
So there really was a Valve spring 4V watercooled Duke/Duc Racing successfully over this side of the pond...
I think that it was called the 'Mezmoquatro'?
Here's a link to the guy responsible for the head work, he's sadly now no longer with us.
MEZ PORTING HOME PAGE
Mr Mansfield ported quite a few of my heads over the years, he also ported the 'Sports Racing' Ducati's which were raced by S.M.B.Hailwood amongst others.
In fact most of the UK's top Ducati tuners used George's expertise, although they usually passed his work off as their own...
Steve R