Alas, I only have so much time this time around, and I need to prioritize.
So, it will be the Grand Circle, so Yosemite, Death Valley, Yellowstone and Teton will have to go from this trip.
After all, my starting point was to see Grand Canyon and the Antelope slot canyons ... and then things grew from there, thanks to you wonderful people

Here's what my current trip looks like this:
http://goo.gl/hXwQl - 1963 miles and 40 hours of driving. Plus the miles in the parks.
I've added in Valley of Fire and Joshua Tree since they're kinda on the way, and I can cut Joshua Tree out if I'm pressed for time. After much internal debating, I'm planning to cut the North Rim out - it would be an extra 200 miles and 5 hours of driving (plus the time there). Going to Antelope slot canyons means that Canyon de Chelly becomes quite awkward and it will have to be some other time.
As for Yosemite being overphotographed: I take the pictures for my personal use, not to sell them, but to record and remember the trip so I don't care about how many people have taken the same shot before.
Café Diablo is duly noted and it looks like I might even make it for dinner time

drmikeinpdx: I would have loved to ride a motorcycle, but with luggage bikes just not that convenient and less safe when leaving the bike for exploring an area.
Lenses: I mentioned the 17-40, 24-70 and 70-200/IS (+1.4x TC), since those are what I have so anything else would be rental or purchase.
For Antelope the plan is to put the 17-40 on the 5D3 and the 24-70 on the 50D (38-112 effective) to get minimum overlap, and not change lenses exactly due to the dust.
Sure, the only light that can fill the GC is that 'sun' thing, but sometimes you need a filler for something and that's where it's a good idea to bring the 580EX. But a flashlight for the pre-dawn/post-sunset treks is duly noted.
There was an excellent shot in the thread I mentioned, that very vividly demonstrated unfocuseds' point about shooting the beautiful warm light on the walls for Grand Canyon rather than trying to capture the sunset. Unfortunately the poster has removed the shot since then.
Car: At 6'6", I'm not going for a tiny car, but a mid-size (e.g. VW Golf, not a Lincoln Town Car) should do fine.
Thanks again for your invaluable input.
And now for hotel and car bookings. Wheww.