I would say better lens, lower camera. You can get amazing lenses with a low end body of a camera and still take good video/pictures. I assume you can with video, I don't have experience in the video DSLR field (my dslr doesn't even have a video option) so I can't say for sure. But I do like a better lens rather than a better camera, as I have a lot of good lenses to go with my camera. One lens I have costs a lot more than I paid for my camera
See what others think, I am curious too. Good luck, I'm sure you'll enjoy whatever you choose.