If I'm understanding your point properly, you are right about lifting beyond stock ride height increasing the torsional load required to maintain the increase in height.
But on the other point you are making, I have never heard of anyone having recurring problems with torsion bar breakage.
The H-D ones that are available from Indy 4X would most likely require fewer cranks to achieve a higher than normal ride height, but IMO, that would be due to their larger than stock H-D construction, giving them more torsional force, requiring less crankage to achieve the same amount of lift.