This Samus Aran Cosplay from Metroid was put together entirely out of 3D printed pieces that were then assembled and styled to give the right effected. The canon even moves! It's pretty amazing the kinds of parts that can be easily manufactured thanks to 3D printing, I think.
This amazing Samus cosplay suittook cosplayer Talaaya two years to design, 3D print and construct at a cost of almost $4000 (yep. That much). She got lucky, really, because one of her friends had a few professional grade 3D printers, and was willing to let her use them for only the cost of materials. Which ended up being a lot: nearly $1,200 for materials alone.
The suit was created with a combination of 3D printing and traditional costume making techniques using craft foam and a thermoplastic material called Worbla.
Canon Test (it moves!) + Full Suit Video
Detailed Glove Close-Up
Since the printer she was using is only 8 inches x 10 inches x 8 inches most of the parts needed to be printed in multiple parts, then assembled with superglue and the joints smoothed with sanding. Just wow to all that work.