These logs are going to be 'stream of conscious' type ramblings for now as I get my thoughts in order on this project. In reality I probably don't have time to attempt this, but we'll do the best we can.

So, sourcing of the power components. 

Batteries: Most likely I'll go after hobby grade cells. Why hobby grade? Well, they are cheap, readily available, and most importantly, come in many different physical sizes and capacities. Flexibility in battery choice will make it easier to hit the weight target and give me some options in chossing the best capacity for the needed up-time. HobbyKing, BPHobbies, and similar discount RC retailers will probably be my main sources for now. 

Charge controllers: Hmm, most likely this will be a Maxim/Dallas part, but there is a chance that that Ti might have something usable in their product lineup. Ti has starting releasing a lot more power components since their acquisition of National Semiconductor a few years ago. I've used Maxim charge controllers in the past, but Ti's products are usually solid, so their could be some good competition here. 

Regulators: We've got even more options here. Ti, Maxim, and Linear (along with several others) make parts that could be good fits here. There are even some companies that make switching regulators that are drop in replacements for TO-220 package linear regulators. While that probably won't be the best option for the final flight config, it might be useful for early prototyping. 

SolarCells: This is a tough one. Spectolab (Boeing subsidiary IIRC) makes some darn fine cells (>25% eff), but even their B stock stuff is pricey. Stepping down to hobbyist grade cells will probably be a necessity, but I'm very worried about consistency of stock. It will be very hard to design a system if I can't get enough of the right types of cells to put together a full system with extras for spares. Lots of questions up in the air about this at the moment.