DAR,
Is there an equivalent standard for "x-wind LIMIT" ?
I think you're missing the point. The definition of the word "demonstrated" is not the issue : what is being argued over is whether operating an aircraft beyond its demonstrated x-wind value is illegal by virtue of the fact that to do so instantly makes you a test-pilot and therefore invalidates your insurance (and makes your under-carriage fall off, evidently ...)
My argument is that if Mr. Cessna says that the MDCV "is not considered to be limiting", then he's saying that because his designers and test pilots have already proven this to be the case.
If I attempt to land with a ridiculous amount of x-wind and the wheels snap off, I'd expect to have a problem with my insurers. However, if the same thing happened a couple of knots over the MDCV,
with the protection of that statement in my POH I'd be quite happy to pursue a claim.
In short, if they meant "limit", they'd say so ...
FF