I have used my trusty Toshiba e570 happily for quite some time on an Arkon universal mount and just upgraded to a new HP iPAQ 2215.
The strange power lead connector gubbins (converter) was annoying me, it stuck out way too far from the the bottom of the HP iPAQ 2215, so I decided to make my own mounting system for it, with power permanently attached.
I took a HP iPAQ 2215 desktop cradle and hacked it about. Where as the cradle Lutz used in Lutz's In-Car Mount looks nice on the dashboard due to it tapering towards it's base, the HP iPAQ 2215 cradle just keeps getting bigger toward the bottom which makes it look a bit bulky and ugly.
I decided to remov the back loop, and the widened front. Added a metal cover plate over the new hole in the front, moved the power connector to the underside from around the back and adapted it to fit the vent mount from my Arkon. The attached photos will make it easier to see how I made my custom mount.
Click any of the photos below to have them pop up and enlarge.