Hi!

There are quite a few products out there. For your needs (and location <img src="/images/graemlins/smile.gif" alt="" /> ) I'd recommend to check out ICP (icpsolar.com). Look for BattPak, and iSun. Not as lightweight as your idea, but much more versatile, economical, and enviromentally friendly.

For real emeregency use I would use readily exchangeable spare batteries for the critical units.

You can upgrade some APC (apcc.com) Travelport solutions (or such) also, but it is almost a complete mobile office. <img src="/images/graemlins/smile.gif" alt="" />