Hi Richard!
I too faced this question and decided to investigate it a bit firsthand.
Using some deformable torque-rating strips leftover from my auto-shop days, some spare dropouts from my framebuilding supplies and some math, I confirmed to my satisfaction that an internal-cam (sometimes referred to as "enclosed") hub quick-release
can generate pretty hefty compressive clamping loads. For another take on this,
http://bikeeng.blogspot.com/2009/02/quick-release-force.htmlIt's easy to confirm end-loaded "pressure" from a quick-release can compress a threaded quick-release axle; that's why I've found it is best to adjust q/r wheel bearings while clamped in spare drops or with some sort of leeway; under pressure, I've found threaded axles compress like springs a few mils and can squash the cones tighter into the bearings. All-thread axles compress more than solid axles in my experience. Unless there is a non-deformable thrust-washer between cartridge bearings to transfer force, they too can be end-loaded by a too-tight quick-release.
When my Nomad arrived, I checked the Thorn-supplied
external-cam quick-release on the rear hub. It was set so the q/r faces contacted the drops with the lever set at 90º. This has since proven ideal for my needs, keeping the hub secure in the frame while allowing the Rohloff hub to turn freely. Please note, external-cam q/rs develop considerably less clamping pressure than internal-cam versions cetris paribus (other factors being largely equal). See:
http://sheldonbrown.com/skewers.html ...and...
http://www.bikeradar.com/us/gear/article/angryasian-death-to-crappy-quick-release-skewers-36417/The external cam q/r works to advantage by helping avoid over-clamping of the Rohloff axle and bearings. Thorn's use of vertical rear dropouts/frame ends reduce need for high clamping tension because the axle cannot slide forward as can happen with ramped dropouts.
Hope this helps.
Best,
Dan. (...who still owns two of Grant Petersen's hand-brazed Bridgestone dealer's countertop quick-release demonstrators)