Canon support the warranty through their service agents. At least, that's been my experience.
My 2 cents. I recently upgraded from an ageing Canon 1000d to a 7d with some new glass as well. With the new glass on the old camera the difference in image quality over the kit lens is huge. As others have said, spend the money on the lenses over the body and avoid cheaper lenses (except for the Canon 50mm 1.8 that someone mentioned, it's a ripper for the price).
The 7d has some weather resistance, a great build quality, fast shooting speed and good ergonomics. However, the picture quality was a bit soft in anything other than bright light and in lower light had vertical banding from a sensor issue. I swapped it for a 70d which isn't as solid but the image quality is much better. I bought the body from my local JB HI FI and had great after sale service. For the lenses I mostly used cameraparadise.com. without any problems.
If you go Nikon have a good look for sensor spots within the first 1000 shutter cycles, especially with the d7100 & d610.
Most of the Pentax range advertises good weather sealing for their bodies and most of their lenses, however I don't know how good the warranty would be if it was rained on and got water penetration.
What ever you go for make sure it can shoot at least 6 frames a second in RAW (and shoot in RAW), has some weather resistance and if shooting from the beach about 300mm at a minimum.
