The D5100 should be fine, I’ve had three Nikon DSLR’s (D40, D60, D90), and it might surprise you to know that out of the three, the D40 was by far my favourite even though it was by far the cheapest. Price and model position means nothing with cameras in real terms.
Don’t worry about the camera.
Selling prints, I’m no expert but I think that’s going to be more a of a challenge than you had deciding on the camera, put it that way! I’ve never tried to sell a print or any form of art, but if did, I think I’d research into what is the most popular online store for prints, learn my way around it, and stick to it. At least until I learned more about which sites deal more specifically in the sort of stuff I wanted to sell.
Good to know on the camera. Thanks!
For selling prints, I think I would have more luck selling at art shows or conventions with a similar theme to my work. Of course, I may just move to Oregon since they don’t have sales tax there apparently. (I hate the paperwork.) Of course, they have state income tax which Florida does not, so I suppose I’m damned if I do, damned if I don’t.
But theoretically, if it was profitable enough, I would be willing to get a truck and tent, racks, the whole shabang if it meant I could quit my day job. I’m sure I would need to do a lot of shows even if it were profitable though.
In practical terms, even getting started would require quite an investment so I’m probably better off sticking to selling 3D content. *cries*