Not specifically an X1, but there are plenty of posts with people running it with the N55 in other models. For example:
http://www.2addicts.com/forums/showthread.php?t=1348316
There is also a Dinan Sport version that works with the N20/N26/N55 (cheap plug... I know someone that has one for sale
). Personally I like having the bluetooth connectivity with the Dinan and not having to open up the device every time you want to change the setting.