Ahhahhaha I'm really happy to have done this cosplay, but I guarantee you I would not have done in if I hadn't been part of a group. I wear this with Koalois (Mikasa/ Levi) and MischeviousMelody (Erwin/Hange). This would have been horrible to make by myself.
Our harnesses are made from professional-grade upholstery vinyl salvaged from a furniture store. Each harness used about 3 yards of 1" strips. The backplates were made by Koalois from two layers of craft foam and a layer of fabric for support. The side panels for the thigh belts are also craft foam. We'll be making 3DMG eventually, though mine will probably not be for a while, since I have a bigger project to concentrate on for Youmacon.
The butt skirts are brown suiting fabric and are worn by threading through the belt loops on our pants.
The jackets are brown suiting, and made from a self-drafted pattern. Mine has a facing in the front panel, with all of my unlined edges serged to prevent fraying. I used Decorbond heavy-weight interfacing in my collar, sleeve tabs, lapels, and pocket flaps so that everything is stiff and retains its shape well.
My patches are entirely hand-made with a lot of time, patience, satin stitching, and heat-n-bond. The white sections are sateen, the green is twill, and the gray is the same line of suiting fabric as the jacket. The back patch is 10" tall, sleeves are 4.5", and the chest is 4" (I think..) I made the base templates in AutoCAD and then drew the unicorn out freehand.
My hoodie is a double layer of white knit, and is probably the most comfortable thing I've ever made.
Wig is from MatchWigs. Purchased our boots (eBay) and pants (Old Navy).