The EF 50mm F/1.0L is a collector's bauble. It might as well be branded Leica for all the good it will do Canon shooters. The new EF 24mm F/1.4L is a much better piece of glass that will lead to better available light shots. Long time readers of this forum will remember when I explained at length why the Leica Noctilux is no damn good for similar reasons, and the Noct is actually sharp wide open.
I have been considering buying a 4x5" viewcam for a while now, but whas has stopped me is that I am really not set up to develop the negatives, nevermind making prints. For the moment, I'm shooting film with my EOS K2. Eventually I'd like to get an EOS 1v, or do something crazy and switch systems. None of that is happening any time soon.
I pretty much agree with all your points on the superwide zooms. At such a wide FoV, faster aperture doesn't matter much and every mm counts. I also find third party lenses suspect.
Any Head Casers got a PowerShot and feeling brave? CHDK Wiki