Effectively the same thing, and portable!
[RIP my Axim X30]
http://www.amazon.co.uk/Power-Only-Charging-Cable-Extension/...
"The CDL-02POWER is a type A male to type A female extension cable with only the + and - power pins connected.
This is extension for charging devices like ipods, Sat Navs etc. It allows you connect the appropriate device cable and charge the device through your USB port on your PC/Laptop with out opening up your webstore, itunes etc. While a device cable has data and power only the power from the extension is carried through.
Please note that due to limitations of 500ma output from a USB port, some devices may take longer than others to charge. "
http://www.idownloadblog.com/2012/05/21/apple-power-adapter-...
(not affiliated)
It's called "3-in-1 charger" here in Europe and it looks like this:
It's even smaller than I thought it would be, and so much more portable than a normal UK plug.
Amazon 5W USB Charger