About the 6d,
I'm reading really bad reviews about the camera and its build qulity and I fear that I'l be missing the "Canon Feel" Which I loved so much and the reason I never Used Straps. you might think that thats stupid reason to judge camera and not by her specs But Had really Good bonding with my 7D =)
Well, I think it might help you to go to a shop and check whether you feel the canon feel
before I got mine, I went to a store and held it (there was also a 5DII and 7D to compare it with, it didn't feel bad, just maybe a tiny bit smaller than I would like it, but a grip helps there)... I didn't do that with my first DSLR (350D) and when it arrived I was shocked how small it is
And then, it depends on where you live and what is the price difference between 6D and 5dIII (plus, as mentioned, if you need (want) the AF of the 5DIII (mainly) and if its worth the extra for you)
and anyway, sorry to hear about your experience, I hate such thieves, vandals...
but good luck with your new camera, happy shooting however you solve your dilemma