Here is food for thought... What if the dollar had somehow been pegged at an elemental level to gold from the beginning?  Would the dollar still be sound money today?  Obviously, a very fragile and subjective peg maintained by central banks did not work.  Gold lost is dominance as the world's reserve currency because of lack of utility but if that utility could have been preserved by scaling gold's utility at a fundamental level vs scaling at such a weak level (USD), then it may have worked.

I believe this is the crux of the whole issue and you are right, there is no precedent for it.  Unfortunately, the only way I see to figure out if a protocol level peg will be strong enough is by trial and error in a live environment.  Theoretically, this should be the last major untested change to the main chain as all other major changes can be done on side chains before being implemented on the main chain, if ever.