A full party of 4 lead by Joebo went and cleared a level 50 greater rift. With great coordination they cleared the rift with only a handful of deaths. You can check their video below on how it all went down.
Their team consisted of two Demon Hunters; Austerity and Uruu, with Joebo as the support Witch Doctor and their tank was a Monk named Barbalel. They finished the rift with 2 minutes and 12 seconds to spare and as of me writing this are #1 in the 4 player Greater Rift leaderboads.