In the interests of karma (worldly not Reddit) having shamelessly made a thread promoting own designs and in respect to pleasant responses I got. I've compiled some of the entries I believe deserve your votes. My designs are not included.

THE DEVILS SHADOW :As much I'd like to win, with some minor tweaks I would love to wear this shirt. Has a great explanation for it too. image link

CHEVRON UNITED :Not sure if the red makes or breaks it (personally I'd remove the top three stripes), but, it certainly draws me to it, would wear either way. I own the last chevron kit (09/10) and they are not unusual for a United kit, vaguely historic. image link

UNITED FOR EVER :Simple, original, different and pretty damn cool. What more could be said. Not sure if intended, but has a historic nod too. image link

slight outsiders:

WORKER BEE STRIPE :Not sure about sashes as City used one recently. I like where this one is going though, with some tweaks it could look really good. image link

THE SLEEK DEVIL :Maybe looks a bit too much like a training kit and is made from the defaults but looks pretty good. image link

MANCHESTERUNITED Needs a rejig but could look awesome, really like the concept. :Cleaned up google translate(you'll see if you click): This time Adidas has given the chance to design a third-kit of Manchester United to the fans. I wanted to design something different from the usual United third kits. I tried to make the design as powerful and clean as possible. image link

There's a lot to dig through so if you find more good ones please link them.

:EDIT: Added direct links to the images for viewing quality, plus the site can be screwy.