In reply to the ant hill mob:
Yep, second vote for the Cineastas (above the Glacier Blanc Hut). I did it a couple of years ago. The approach is horrible scree and very loose but once you're on the ridge it's very nice.
There are rigged abseils (2 or 3, down a loose gully, back to the snow on the other side of the ridge) before the end-point defined in the Alpine Club Guide and we managed these on a single 50m rope.
It can be done in a day from the valley but also makes a nice route on the way up to the Ecrins Hut. We used it for a bit of acclimatisation and stayed at the Glacier Blanc Hut then went up to the Ecrins Hut the next day to do the Barre the day after that.