My Solution: Latch Cable Pull w/Pics
I used a 10" length of 1/16" cable that I can easily reach just behind the headrest on both LH and RH sides. Now that I've completed it, I think 12" of cable might have made it a little bit easier to reach and flush with the seat back, but this works fine.
I drilled a 1/8" hole through the post on the latch, looped the cable, and crimped the cable connectors.
I agree that there is not a huge amount of space back there, but I now have easy access to my amp mounted on the back wall, and some blankets and other "just in case" emergency stuff I keep back there.
2011 F-150 Lariat SuperCrew, Ecoboost, 4x4, 3.55LS, Dark Blue Pearl/Adobe, Factory Stereo +upgrades, WeatherTech FloorLiners, Billet IC Grill, Fold-a-Cover G4 Elite & Linex, AMP BedStep/BedStep2/BedExtender/PowerStep, Ruggedliner, RoadMaster, Airaid SynthaFlow Drop-in.