You see, the $500 backpack portion was slated to ship on October 13th but is listed as out of stock as of this writing. If you're one of the first to buy the PC at this point, you'll have to either hook up your VR headset the old-fashioned way or (gasp) make do with staring at a conventional screen. It's far from a hardship -- if you can swing a $2,500 PC, a $500 backpack and a VR headset, you can probably afford to wait. Still, it suggests that HP wasn't quite ready to handle demand.