It's $174.95. I don't think there are any other adapters that give you control over the aperture with Canon EOS lenses on an NEX camera; the Birger mount is supposed to, but it's still MIA and is going to cost several times this.
The interesting sentence in the description is:
This adapter has an aperture, which offers manual adjustment of exposure.Does that mean it has a diaphragm of it's own, or that it controls the one in the lens? What's with the "123456" numbers on the side?
Bower's own website doesn't seem to have a listing for this item yet, though it appears as a "New" item in the PDF of their catalog.
NOTE: They seem to have two versions of this adapter, one with no aperture setting, which sells for about $87, and this one with the aperture setting.
Can someone with an NEX-FS100 please buy one and let us know how it works? Thanks!
B&H: Bower ABANEXEOS Adapter for Canon EOS Lens to Sony NEX Camera with Aperture