While I'm a proponent of PV cells (installed them on my house in April in a grid-tie system), the small-scale technology for making them practical for recharging batteries, powering radios, etc, isn't quite there yet. Two summers ago I bought one of those PV-powered radios as I was at a base camp in the Oregon Cascades for a couple of months and wanted to listen to NPR in the evenings. Even when exposed all day to sunlight, the PV cells provided only about 5 minutes of radio time. Fortunately, it had a hand-crank generator as well. REI's excellent return policy allowed me to return it on the way home as I drove thru Bend.
As for lithium batteries vs. NiMH and alkaline - I don't think lithium have an inherently greater capacity than the others. Their primary advantage is that they are not nearly as susceptible to reduced output when exposed to cold temps. The down-side is they're rather pricey and single-use only, unless rechargeable lithium AA's and AAA's are now on the market. The Sanyo Eneloops are excellent rechargeable NiMH batteries as they use the newer technology while allows them to hold a full charge for longer periods.
Follow-up:
I checked out the Petzel crampons - for general mountaineering (which your proposed trip is) less is more when it comes to crampons. Those 12 pointers are designed more for technical ice climbing. Unless you've experienced (and very lucky) you stand a good chance of either stabbing yourself and/or shredding clothing over an extended trek like the one you're considering. Even the BD Contact Strap are overly aggressive, IMO, but Grivel G10's are tough to find. You might check the Mountaineer shop - can't recall the name of the town, but it's in the Adirondacks. They had quite a stash of them. (Grivel had contracted with a company to do their North American distribution, and it went out of business a few years ago. I think that is getting resolved, but refilling the supply channels seems to be taking some time).
Personally, I think you're overdoing it on the boots. You really don't need to spend more than $300 or so on double plastic boots. I believe that Scarpa Inverno's are still the gold standard on Everest.
You can extend the warmth of plastic boots with gaiters - not the type OR and MH sells, but the type with a neoprene bottom. They come either insulated or non-insulated, and are a bear to get on, but ... once on, you leave them there (some hardcore types glue them to the boot) but they can add 10 degrees to the boot. Even a good pair of insulated ones from Wild Things only runs about $100.
- Just looked at MEC's website - here's a link to the type I describe above -
above. 
