Tom, Awesome, an example of all that is good and useful on the internet!
The 2 route links you give are 2 of the main ones I've used for planning the route, which has come out more or less a mix of the 2. Same as yours till 1/2 way through day 2, then more or less the same as Jamie's at Ridethealps to Evolene,day 3 Pas & Basset de Iona to St Luc, day 4 Pas de l'Illsee then back onto yours for the Augstbordpass to St Niklaus, then day 5 up to Zermatt and bankruptcy...
My main problem had been sorting out the accommodation, the majority of online search engines look in the surrounding area, and 10km in a straight line can be an auffy long way in the mountains! I found it hard to believe that there were no gites in any of the towns when it's one of the main walking areas in Europe.
I live in Chamonix, so had all but 1 of the maps anyway for ski touring (swiss ski touring maps are a thing of beauty for anyone who hasn't used them, but they colour them in for winter snow levels not summer, which adds something to the MTBing high pass rideabilty guesswork)and also means I can pressgang a mate into driving round and picking us up to save on the train fare.
We're aiming to start 2nd weekend in September to balance the lifts still being open, the trails being a bit quieter and me having enough time to recover from running the C.C.C. the weekend before.
Looking forward to reading ChrisE's report too!
If I can help anyone with Chamonix info in exchange, I've got the http://www.chamonixbikeblog.com/ which also occasionally has bigger rides. (I'm quite proud of the Tour du Mont-Blanc one!)