Newly released/announced for the Nintendo DS from play asia:

The Travel Pack is the ideal companion during travel, even in foreign countries. Because of the clever combination of car charger and USB cable, you are no longer bound to foreign country outlets and adaptors. Just put the USB charging cable in a USB device and the adaptor will make sure that there are no more interferences in gameplay.

Price: US$ 14.40 / Usually ships within 5-15 days