Yes I have, and it's smaller. Not by much, but it is.
The 1D3 ends up 0.61x (0.76x magnification, and it's a 1.28 or something crop).
The 7D is 0.63x (1x magnification, 1.6x crop).
That's why I always find people talking about 1D finders being big hilarious. They're smaller than (7D, D300...