In reply to Cathy:
I did it unguided in 2011. Second Nick's suggestion to go to Valsorey, much more interesting and also more 'mountaineeringy'.
We couldn't get into the Vignettes hut so we stayed at the bivvy hut a bit further on. The name escapes me but it's over the Col l'Eveque from vignettes. Made a pretty long day from Chanrion mind.
We went via Champex. If I do it again I think I'll use the Grand Lui variation.
Feel free to PM me for more info if you want.