One added comment, which is an important one in my book, concerns the 5DIII AF system. If you get the 17-40, 24-105 and 100-400, none of them will take full advantage of the AF system of the 5DIII. A 16-35 2.8, 24-70 2.8 and 70-200 2.8 would.

Also, just an observation, it seems to me you are looking at the 5DIII as the long term investment and the glass as something you will swap in the not to distant future. I believe you should reconsider. Glass lasts much much longer than a body. Ref. a 6D outperforms a 1DsIII on everything but weather sealing, at a fraction of the price. In a couple of years you will see a very high megapixel camera with 1DX class performance, around the 5DIII price mark. I believe you would want to have the higher quality glass then.