This was my contribution to this year's (2014) Secret Santa over on the Fwoosh.
Lady Sif (movie style):
I built her on a Marvel Select Rachel Summers Marvel Girl body with WWE Kelly Kelly hair.
Sculpted all the armor, and loaded her with accessories.
I knew with a character like SIf, accessories would be essential. Noteably her sword and shield.
These gave me some trouble as the original figure wasn't really "equipped" to hold things, and I dian't want anything to chip, break, or scratch the paint. I came up with the idea to drill a small hole in her closed fist, and used a big indstrial staple that I cut apart as needed. I sculpted the sword so you insert the pommel piece up through her hand and into the blade of the sword. Not entirely happy with how flat and "paddle like" the sword is. But the thickness was due to the necessity of needing to fit the wire inside the sword. I was going to sand a bevel on the sword's edges, but lost my nerve at my ability to make it look nice and even. From the top view of the flat of the blade I think I got the shape about perfect.
Next the shield. I actually made this first in several stages. I cut some thick blister plastic to the proper shape, then sculpted the face on top of that. I also made a special sword hilt and blade tip for the shield. In the movie, the shield has kind of a sheathe on the back where Sif stores her sword. So using the same concepts as the full sword, I made two pieces that would fit in specially designated holes on the back of the shield.
Now, about attaching it. I bought a large number of VERY small neodymium magnets. The shield is magnetic to a corresponding polarity in her left bracer, and another on her back. The weight with the sheathed sword hilt tends to want to rotate it forward a bit, but as there was a lot of experimentation here, I'm very happy with the end result. Yes, to put it on her back, you have to tern her head slightly to move the hair, but shield-on-her-back-thousand-yard-stare was pretty common in many reference pics.
I also gave her two very specific Dark World accessories. In the "secret" scene with Sif and the collector she delivers the aether wearing a heavy cloak. I made the cloak out of felt and it closes with another set of magnets. The polarity is such that theroetically it would also attach at the back attachment point. And of course the aether itself. Assuming galactape, my recipient, has the ML Red Skull and Movie Star Lord, he now has three of the infinity stones.
Lastly, the little bronze battle horn. It's nothing special, I merely had a small amount of epoxy left after on sculpting session, and rather than waste it, I made a little flower inspired horn.

but what you really came for are the pictures (I appologize, I forgot a back shot)