Originally Posted by JohnG
If you want to do portrait work, even of pets, I would suggest getting and learning how to use strobes / umbrellas/ reflectors would do more to improve your portrait shots than upgrading your current body. Your lighting, poses, backdrops are going to do more for the saleability of your images than a newer body will.
As an example - there's a guy who does photos at my son's daycare. The camera and lenses I routinely use are far better than what he's using but I buy from him anyway. Why? Several reasons:
1) he goes to where my son is
2) he has a good lighting setup
3) he has GREAT backdrops and props - not the boring muslin patterns or whatever you see in a lot of school photos. If we swapped out his camera/lens for mine the photos would be a bit better but not terribly so. In fact, most parents probably wouldn't notice a difference. Portrait work is far and away more about lighting, then lenses and last of all camera body.
So I'd start looking at building and learning a portable studio setup before you worry about camera upgrade.
Very interesting take and example. Sounds very logical.