[BagCamAddict]

1. All first-ballot Trump delegates go along (and they aren’t required to; their pledge is only to support the candidate’s nomination, not miscellaneous rule-change motions); and
2. Some other, presumably non-Cruz delegates join in by the hundreds.

You're right, that's not likely regarding changing the rule to 1100. But it is certainly possible if all the #NeverTrump delegates join together to change the rule to 1400, thereby blocking Trump from winning on the first ballot... and allowing them all to flip to Cruz on the second ballot.

[pogo101]

I hadn’t thought about a rule change to INcrease the required share of delegates. It’s possible, but why? We’d end up even more torn apart, like the Dems in 1924 (when 2/3 was required to nominate).

[Brookhaven]

If they change it from 1237 to 1400, it will be the end of the Republican party—literally the end. Not just for the presidency, but senators, congressmen, governors, & dog catchers. The backlash against the GOP would be so large that people would refuse to vote for any GOP candidate at any level in November.

I would hope cooler heads would prevail in Cleveland, but you never know.