I noticed two things, 1) is that the trojan mask has a month long limit, 2) is that i have never once seen anybody wearing one, And i think the reason may be because people tend to not purchase limited time items because they feel they can get something as good or better forever. I understand why it has the timed usage, It's to give it a more unique and special feel, like this is something so very limited that it is worth having for such a short time. Also costumes unlike weapon/trinket slots do not actually help you in game, Which is why people are willing to buy them even though they are also limited. I feel it's a big shame that these certain item that are limited (i am sure there are others, but i can't think of one off the top of my head) are being overlooked and neglected because they have this "flaw", I would love to see them as permanent costumes and to see people wearing them all over, But hey that's just me.
It would make me very happy to hear other players opinions on this topic, And maybe one day it will become a permanent costume.
I think it'd be neat to have the ability to buy standard style Trojan helmets. The only thing is I dunno how many accessories would work well with something like that, but HEY why let that stop them?
Maybe a Frosty-themed Trojan hat with a bit of ice stuck to it, in reference to Maulos and his neato iceyepatch.