Update Oct 1, 2012 9:30PM: Barkley can't come home tonight because his clotting factors are not good enough. He'll have to stay tonight and may be able to come home tomorrow. He's mostly alert and wants attention so I spent about a half hour in the floor with him hooked to an IV to let him know I was still around and hadn't abandoned him. Last night when I left him, his head looked a lot like a bowling ball from the swelling; that has reduced a lot and he's eating. I got another patient's person to take a picture of the little guy:
Update 2 October, 2012 12:25AM: Got a call from the vet and Barkley's clotting factor improved and he said I could come get him. The little guy is home running around chewing on a rawhide bone. When I went to pick him up, he literally ran over to me. This was far, far different from the little puppy in shock from a rattlesnake bite that I took to the hospital Sunday night. I may post a picture of him with the remaining swelling, but first Barkley and I are going to bed.
Don't ever say anything bad about an emergency veterinarian.
Update: I put together a blog post about snake avoidance training <link>, do this if you have any worries at all about your dog. If you take long walks in the wilderness or take it camping with you, it would be a really good idea.