I was able to slap this together in little under an hour. I probably spent the most time procrastinating whether to solder in a USB socket or not. Since I have run out of those in my lab, I decided to directly wire up an iPod cable.
If the photo does not load: http://twitpic.com/xdc8k
-2000mAh Li-Pol pack, with around <8% per month discharge rate.
-Rechargeable via USB.
-Can power an iPhone/iPod at the same time.
-USB charging from PC -> device charging at 100 mA
-5-7VDC adaptor input -> device charges at 300 mA
-LED flashes when battery is charging; stops when fully charged.
-No on/off switch! (granted, there is quiescent current drain by the DC-DC booster...whatever )
-Works with all iPod/IPhones - even older models. They all use 5VDC input
I'm sure if I took the time to bridge both the Li-Pol charger circuitry and the 5VDC boost circuitry onto a single PCB, this could be made much smaller. As a prototype however, this is good enough Will post some better pics when time permits.