Great pics by the way, but you mentioned the D600 gripped still felt front-heavy. I shoot with a 7D+grip+24-70 mainly and it feels really balanced, but I upgraded from the T2i because the body was just too small and did not feel comfortable. How do you find the lighter and smaller D600 vs 7D, in terms of ergonomics?
7D ergonomics are MUCH better than the D600. The 7D grip in particular is, for my hands, nearly perfect. The D600 grip is just too small.
I haven't tried the battery grip yet... I'm hoping that improves things.
Beyond the grip the 7D also has superior control placement. The "wheel" on the back of the 7D is really good and the "joystick" on the back of the 7D is superior to the joystick on the D600. The D600's joystick is still really good, but a bit harder to work with gloves on. My main issue with the D600 controls are that quite a few of them (most notably AF mode selection and ISO selection) require the use of your left hand... whereas on a 7D almost everything can be performed using only your right hand... leaving your left to hold the (possibly heavy) lens.
Don't let all of this scare you off though. This is really just nit-picking. The D600 is not "attrocious" to hold and handle... just worse than a 7D. However... the image quality is MILES and MILES beyond a 7D and MORE than makes up for any shortcomings in ergonomics.
A lot of the issues with the button placement on the D600 can also be remedied through customization. Almost all of the buttons on the thing can be completely remapped to do something else. So you can customize it to your needs.