There is already Linux though, i have 2 PS4', one on the latest, and then the 1.76 firmware, which i've tried using linux, an PSN playground, which is fun, but the gateway settings/port forwarding is a very annoying process, but i hope PS4 gets jailbroken, but has no spoof as annoying kids online will ruin every game if they get their hands on mods IMO.. i hope it never gets spoofed, and people just use mods/tools offline. But, it'll be interesting to see the bases and layouts of the menus for next gen consoles, very unique/different menus.
Also, 3D capability should be some fun!