Can't help you with the folding keyboard. I had my heart set on the Jorno which was previewed at CES in 2010? It never came to market though and is now fully funded through kickstarter: Jorno.
For the record, I went with the Logitech Tablet Keyboard and it has worked out extremely well. Yeah it doesn't fold down to a deck of cards: 5 1/2" (130 mm) x 11.3" (288 mm) but it fits nicely into my backpack and it feels solid even under the pressure of my fat fingers.
On the battery side, I've been extremely impressed (and happy) with New Trent. After you find one you like check out the Amazon reviews. People seem pretty happy with them.