Dyable backpieces
From an Anet Dev regarding being able to dye back pieces. Note this post was from before they had their account marked as a dev.
It’s extremely hard to alter the engine so backpacks are dyeable. As far as the engine is considered, backpacks are considered items (like weapons) and gliders are considered effects. The engine needs to be fundamentally altered from the ground up to allow for item dye channels. It’s not impossible, but not easy. To add to this, the Shining Blade glider was designed on its own and after it was modeled one of the artists saw that it could be turned into a backpack for the players to enjoy. I think lazy is an inappropriate term for this situation when someone went the extra mile. However, I do understand your frustration with not knowing it couldn’t be dyed. That should be more clear.
You will find more posts on this topic from the dev throughout the thread linked.
(edited by JustTrogdor.7892)