dc-dc ps iv=~1.2-7.4v ov=5v?

[John N]

I'm interested in a small power supply that would take a range of input voltages, and output 5v.

The application is a flexible USB charger. Something that could take 1 or 2 AA cells, or 1 or 2 18650 cells and provide a regulated output to charge a small electronic device (iPod, cell phone, etc.) via USB.

The idea is to have something that isn't too picky about input voltage, but provide a consistent output voltage.

I'd prefer something off the shelf, but could do a kit if needed.

Something similar but with a 12v output would be of interest as well (iv=6-14.8v; ov=12v).

Any thoughts?

Thanks,

-john