I've begun work on a pretty simple mod that adds some additional bonuses to wearing power armor, primarily carry weight and melee/unarmed damage, with the tradeoff that you have to keep the armor charged or all bonuses aside from radiation and damage resistance go away, and are replaced by a very large hit to agility. It doesn't seem like that original of an idea though, and I wanted to make sure there wasn't already a mod out there that did the same thing. The closest I can think of off the top of my head is FOOK's power armor night vision that runs off of energy cells, but this will be different. If you can think of one let me know.

As far as details go, there will be a home charging station that is portable, but only works if you set it up in your Megaton or Tenpenny player home (and maybe a few other locations that would probably have access to power, like Underworld and the Citadel Lab). When in the field, you'll be able to partially recharge using fission batteries, energy weapon ammo, or ceramic ultracapacitors (lightweight, high capacity, rechargeable, but expensive batteries available from Durga at the Citadel). One charge should last about a day (16 game hours), but will depend on how often you run and how much weight you're carrying. You will actually be recharging a quest item, the PA Power Inverter, so the charge will carry over when you switch armor.

I'm trying to make it as easy as possible to maintain compatibility with other mods - I'm pretty sure that if I wanted each set of armor to have its own charge level, I'd need to give them all object scripts, whereas this just requires altered object effects. FOSE will be required. If there's much interest, and I get permission, I'll add compatibility for DLC and some major mods.

*Edit - I'm also considering making some of the bonuses part of a modular upgrade system. There would be melee damage, carry weight, and solar recharge modules, etc., that you could purchase, though they would add to the power draw.

It sounds like a neat idea. I cant think of a mod that does exactly what you want. There is um, coyote reflex power armor -- That utilizes fose, from its description it sounds as if it might be a good starting point for you. http://www.fallout3nexus.com/downloads/file.php?id=3365

Note: I have not yet tried that mod, but it seems fairly popular.

Thanks. That mod does do some of the things I was thinking of (and a number of things I wasn't), but I think there are enough differences between our ideas that mine will still be worth doing - besides, I've already got mine more or less working. I have yet to implement a number of features (those could take some time), but the core scripts are written and I'm using it with my current character. I like that that mod was able to make the armor model reflect the installed upgrades, but that would take a lot of work if you wanted to implement it for every set of power armor in the game.