Not sure when this happened, but this morning I noticed a number of east coast TATL upgauges from 781 to 77W this summer (I checked random dates in mid-July and early September):
EWR-FRA (second flight on a 76L)
EWR-CDG (new second flight added on a 763--has this been reported previously?)
EWR-BRU
IAD-FRA (second flight on a 772)
Consequently EWR-LIS and EWR-ATH see an upgauge from 763/764 to 781. I didn't search every last route, but I wonder where else they're planning to redeploy the 781? Accounting for the EWR-LIS and EWR-ATH flights, there should be two additional 781 frames freed up from the upgauges listed above.