In addition to the link provided above, this question has been revisited here:
Zak Middleton has explained that while there will likely not be an “out of box” solution for a custom shaped root capsule component, you can likely create a solution yourself starting here:
UCharacterMovementComponent::PhysicsRotation() with custom checks to see how far towards the rotation the capsule may turn
The following article explains in much greater depth why the idea of a custom shaped root capsule component, like other apparently good ideas, is not already integrated into the engine:
https://headcrash.industries/stories/why-your-idea-might-not-make-it-into-ue4/
In the meantime, anyone who feels they have a viable solution is welcome to submit their solution via GitHub or sell it as a plug-in through the Marketplace.
Thank you for the feedback regarding this issue. It has not been completely disregarded and may eventually be incorporated into the engine.