In case it runs a locked Win CE Automobile version or similar, I wonder if we could run an application to call another gps software on it...

Yes, it runs Windows CE Automotive 4.2.

CE Automotive is pretty stripped down and will not run any standard 3rd party CE apps because it lacks the GUI libraries.

There is no way to run any other application on it because it doesn't have any kind of program launcher in it. You'd have to hack one in.

Assuming you were even able to get the standard CE library DLLs into the unit, you won't be able to run most commonly available CE apps because most of the GPS software is compiled for ARM processors while the Z-series uses the Hitachi SH4 processor. You would need to use an open-source app and compile it for SH4.

Best unit for hacking is the F-series, because it runs the full Windows CE AND it has an ARM processor. Oh, and it also has Windows CE Explorer built-in so you can launch 3rd party apps.