The reason for a DSLR might be the faster workflow by better technical quality through the larger sensor. Focusing is also faster. The Canon 5D-II is a marvel in focusing but it's beyond your budget, since a good lens is as important as a good body.
Why don't you try the Nikon D90 which is a very good stock machine at 12MP? You will have ample budget left for a good lens with it, like the 18-105mm f/3.5-5.6G ED AF-S VR DX Nikkor Zoom Lens. If you plan doing models in studio, there is even budget left for a 50mm prime lens, which will always be better than any zoom. posted in Need advice! I'm planning to update my G9 to a DSLR