Hi hillsider,
Hmmm I can understand the prone problem having neck problems myself after two lots of Whiplash injuries the last being March 28th 06

Now this is my Swedish Mauser 6.5x55 set up with high mounts and a 7x50A Meopta scope


As you can see the mounts are quite high yet these steel mounts have yet to allow any movement of the scope. The mounts unfortunealty are Hilvers which unless your lucky and find soem old stock no longer made as such although mounts of the same design are made under the Lynx brand but as I hear the quality is not up to Hilvers

.
Have you considered the Apel mounts? these are rock solid and come in dofferent ring heights and even the stabdard mounts and rings are not that low. As you can hopefully see in this photo which has Apel EAWswing mounts fitted to a S&B 6x42 scope:-

Apel also make a Roll off type of mount which is a little cheaper as seen here on a Parker-Hale 1100:-

These are 30mm rings holding a Tasco Titan 3-9x42 scope.
I tend to shoot with an erect head position and just use a chin rest instead of a cheek weld. It might just help you but it would be best to find someone with a rifle so set up and see how it feels before committing to anything. Good luck with your search.