iTunes Utility - Merging Libraries

I would like to merge three separate iTunes libraries. Here is more information:

• Currently have 3 separate iTunes libraries on 2 laptops and and dekstop.
• Want to merge all three onto the desktop (i.e. it has all content), while maintaining the other two laptop based libraries as-is.
• I want to avoid getting a slew of duplicates within the merged library.
• I am not concerned about maintaining the library (i.e. playlists, etc.) on desktop.
• I am not concerned with maintaining perfect sync, so could repeat the necessary procedure periodically to remerge libraries.

I am ok with using the command line, Python or applescript if that's the way to go.

Script Method: http://guides.macrumors.com/Keeping_2_iTunes_Libraries_in_Sync

I actually use this technique myself.

Creates a "carbon copy" of a library on another machine which you can then sync to reflect changes.

Works best with two Macs, never tried it with a PC.