bigbop

Although this is for users with a Holux GPS, this cable has the level-shift module and a car charger adapter for a really good price.

http://www.suntekstore.com/convertible-cable-with-car-charger-for-holux-mouse-gps-receiver-dell-axim-x50-x50v.html

Users would need to change the end plug of the serial connector but hey, most of the work is already done with this cable.

This is for the x50/x50v/x51/x51v series.