The 7D has a better build quality and sealings than the 5DII and equal to the 5D3 and 1Dx.
Ummm...no. The 7D has better build quality and sealings than the 5DII and equal to the 5DIII - that part is true. The 1D X is a substantial step up in both build quality and weather sealing. The ranking is 1-series >> 7D = 5DIII > 5DII = 50D/60D.
Hard to say exactly given the production 1Dx isn't even out yet, no? What is going to be different in the 1Dx from the 5D3 sealing-wise?...because my 5D3 is exactly the same as my 7D in terms of housing (from what I can see/touch at least)
I've had the opportunity to play with the 1DC (essentially a 1DX) and it feels substantially beefier than the 7D.
I'd have no qualms about using a 1DC as a blunt object to fend off thieves. I'd be a little hesitant to do so using a 7D. But then again, there are plenty of DigitalRev videos that show just how durable a DSLR can be.....