Bit offtopic to the current discussion, but it seems to me that we can actually quadpack Siper Ü-1 if we design a narrower-taller booster. Siper Ü-1 is 238mm without booster (slimmer than the ESSM with 254mm) and 370mm with that chunky-short booster.
I want to see that quadpackable 100+km...