In reply to potted shrimp:
OK, here's few info I hope may be useful
1) Maps for the Italian side of MB - use only "Monte Bianco - Courmayeur" 1:25k from l'Escursionista Editore (it's available from Cordeè, on Internet or in Chamonix / Courmayeur). Don't bother with anything else, as l'Escursionista series of maps for the NW Alps has the latest and most precise altitudes, and the best job in terms of trail indications etc etc. IGN does a fantastic job for the French side, but for copyright reasons uses outdated data for the Italian side. Avoid IGC / Tobacco etc it's cheap stuff made for hikers (and it's not even that good for them). Swiss maps are beautiful (much better in aestetical terms than anything produced in Italy or France), but - as usual - are good for Switzerland, not Italy or France.
2) Position of Crippa / Lampugnani bivy huts: "Marco Crippa" (the lower one, put there in 1980) is at 3850m, while "Giuseppe Lampugnani" (the higher and older of the two) is at 3860m. The position of the two is well visibile in this picture, courtesy of my friend Olivier
http://www.summitpost.org/images/original/181378.JPG
as you can see, they're near the border of the spur coming down from the Pic Eccles to the Brouillard glaciers, and if your're coming from Col du Freney and stray too much to the R, they're easy to miss.
3) Cleaning, maintenance etc of the bivy huts on the Italian side. Bit of a problem here. The majority are property of CAAI, the Italian Academic Alpine Club, an elite group with a glorious history, but basically not enough money to keep the maintenance of these structures. The Courmayeur/Aosta guides keep a yearly program of cleaning / small maintenance of the bivys, called "Mon Bivouac", I believe it's sponsored by the VdA administration, and I'm aware that few individual guides (Matteo Pellin among them) do now and then some "unscheduled" maintenance of the bivys that are property of the Courmayeur guides (Crippa + Jachia). But that's all. These structures are put there for free use from the climbing community, and it's up to the climbing community to keep them clean and in a workable state.
Personally, I believe Crippa/Lampugnani are a problem more than an asset, as they tend to attract a lot of people in an area that its remote, dangerous and easy overcrowded. They represent a safety belt for the Innominata crowd (all four of them), but may also lull some people in a false sense of security.
4) Brenva bivy hut - the most complex part of the loooooong approach is traversing the two torrents coming down from the Dar Deso' and Dar D'Amon plateaus. The passage may be impossible because of the water. There's an alternative passage higher up with a bolt. I'm not going to give the precise position anyway, as in case of high water volume can be dangerous event that way.
Hope this may be of some help.