Yes. Acela 1 power cars are capable of pulling 8 total, and there was *briefly* talk of an additional production run of carriages to lengthen the sets from 6 to 8 cars before the cost projections flunked. Aveila power cars are capable of hauling 10 total, and are much easier to swap out than the hard-bolted A1 sets. So a future supplemental order (as previously noted, a possibility because Alstom's production line will be hot for the next 8+ years pumping out 100 near-identical Aveila Horizon trainsets for France) could allow them to set aside a few super-long 10-car sets for the very busiest schedule slots of the day...and also short some sets to 6 cars if they want to initiate Night Owl HSR service on a light-patronage time slot.I think there's 8 long cars between the 2 power cars. The older trains only have 6 between the 2 power cars.
For comparison, the longest Northeast Regionals go an absolute max 12 cars.