On stage at the AMD E3 2015 press conference, AMD's CEO Lisa Su announced the Radeon R9 Nano, a 6-in PCB small form factor graphics card that will feature "2x the performance per watt of the R9 290X" as well as "significantly" more performance than the R9 290X.
We are looking for more information but because its branded R9 I don't know for sure if it's Fiji or Hawaii. I would assume that the advantages of HBM for form factor and power efficiency would tell us it uses AMD latest GPU in some cut down variation.
Availability later this summer.
UPDATE: Sources on the scene confirm it is Fiji powered!