Quantifying the piezoelectric effect of ceramic capacitors
The answer finally comes as two blog posts from the TI Precision Hub blog.

It isn't a laboratory-grade test, but the post looks at the effect of dropping a known mass from a known height on a PCB with differing capacitors. Accordingly, it's dealing with a "unit impulse" test rather than low frequency vibration, but the results are nonetheless interesting.

A standard X7R capacitor caused a spike of 120mV on the output. Owch! Special "soft-end" ceramics exhibited about 80mV, whereas tantalum and film capacitors caused no measurable effect. Missing from the test were C0Gs, which I would have really like to seen.

This adds to documents from AVX  (and more) as well as more qualitative documents from ADI, AT Ceramics as well the aforementioned Kemet paper.

This isn't quite over the frequency spectrum I was interested in, but I think it's as close as I am going to get without attempting an experiment myself. If someone has this information, I'll un-accept this answer and happily give them my vote.