You may want to check out Jay's Costume Request Thread, up in the dev corner. The Dev in charge of costumes checks in there fairly frequently to look for more ideas. It's long, and has a lot of suggestions in it, but that is the place to go.
Let me never fall into the vulgar mistake of dreaming that I am persecuted whenever I am contradicted.
~Ralph Waldo Emerson
"I was just the one with the most unsolicited sombrero." - Traegus
These are the threads started by Devs that cover what you're asking for:
Noble Savage's All Things Art threads:
http://boards.cityofheroes.com/searc...archid=6083071
Jay's Costume Request Thread:
http://boards.cityofheroes.com/showthread.php?t=115275
Jay's Costume Bug Fix Thread:
http://boards.cityofheroes.com/showthread.php?t=127719
"Null is as much an argument "for removing the cottage rule" as the moon being round is for buying tennis shoes." -Memphis Bill
Cottage Ru... Oh... wait. Wrong thread. >.>
Yup! What Lemur and Aett said. By all means, FILL that thread with suggestions, Sky. I'd love to see everything you come up with! =-3
-Rachel-
Awesome, I'll check it out 
Thanks all
Hi everyone!
Ive been playing CoH for about 2 years now, and although I dont considered myself a seasoned veteran, I have come to a point in my character creation that Im sure every long-time player comes to. It seems that every time I make a new toon, I get the costume ALMOST right and then think, man, if only they had Im sure Im not alone in my desire for that 1 costume part that would make the whole picture come together into the masterpiece I imagined, so I wanted to start a thread solely dedicated to ideas for new costume parts.
Hoodie shirts? More tattoos? Jewelry? Hook swords? I want to hear every one of the thousands of ideas that are out there. However, with all those ideas things could get a little out of control, so I thought we could establish a little system for suggesting things, much like in Lady-Jades thread for ideas for new power sets. Heres what I was thinking:
Name of the costume part: what you think it should be called
Region and category of the part: what part of the body and under what sub-section the power could be found (i.e. Upper body: Baggy: Hoodie shirt)
Description: if the part requires some description, a quick synopsis of what it looks like.
If you have come across an picture example of what you mean and you want to post it as a photo or link, that would also be fine.
Looking forward to hearing everyones ideas!