I have seen the b-Power stick and variants, what I don't understand is how a single AA 1.5 volt battery can power a device that requires 5v?

Maybe I should try and translate the Turkish reviews.

For my Zaurus I use a 4 x AA holder - bearing in mind that rechargeable AA's are 1.25v - which works remarkably well. If the b-Power made a 4 x AA version I would have one.