Tartare
For the 747-8, the crown area aft of the upper deck 'hump' has been provisioned to allow sleeper units (this required the relocation of some ducting and equipment). To the best of my knowledge, none of the airlines that have purchased the passenger version of the 747-8 have plans to take advantage of this, however at least one VIP operator has installed sleeper units in that crown area.
The sleeper units in the 747-8 (and the similar crew rest areas on various aircraft including the 747-8) are not allowed to be used for takeoff/landing due to the lack of evacuation provisions.
The 747-8 still has one ace in the hole - the Freighter. While airfreight remains soft, if/when it recovers if you want something that can carry more than ~100 tons, the 747 is the only game in town (the 747-8F is good for ~140 tons).