Here's a PM option I've recently become aware of:

http://www.microsporttech.com/product.php

It is set to come out next year I believe and orders are being taken in advance. Please note I have not seen any data or studies on it, but just figured I'd put it out here as an alternative to consider.

If, and it is obviously a big if, it does what it says, then it would be extremely portable, light, and useful.