Stiffness of linear rail options

I'm looking for data on the stiffnesses of the different rail/bearing options: V-rail/V-roller, CNCRP-style flat bar/carriage/skate wheels, supported round rail, and profile/square rail. I'm guessing that's the general order of stiffness.

So far, I've only found good info on profile/square rail:
Slocum's book: Precision Machine Design - Alexander H. Slocum - Google Books
NSK LY15 light preload: 137 N/micron (780k lb/in)
NSK LY20 medium preload: 196 N/micron (1120k lb/in)
THK HSR 20TA medium preload: 490 N/micron (2800k lb/in)

Hiwin AG rail on page 43: http://www.automation4less.com/pdfs/hiwinaglg.pdf
AG15S Z0 (very light preload): 10 kgf/micron, 98 N/micron (560k lb/in)
AG20C Z1 (light preload): 24 kgf/micron, 235 N/micron (1340k lb/in)

For supported round rail data, there is this youtube video from Thomson: https://www.youtube.com/watch?v=rq4Pis6Zhf4
The vertical stiffness of that profile rail is 800k lb/in, and the supported round is 210k lb/in.
Thomson has a plot of their heavy duty XR bearing stiffness (again, vertical push), but I've not seen anything else on supported round.

I imagine supported round is more flexible in the lateral direction as the trapezoid base bends? And also the vertical tension direction (pulloff), as the open bearing opens up slightly?

Has anyone measured the stiffnesses of V-roller/V-rail or CNCRP/flat bar/skate wheel designs? I'm mostly interested in the latter, for cost reasons, of course.

Or from the experience side, has anyone built a very stiff machine using flat bar/skate bearings and/or supported round rail?

Thanks for any leads,
David