Is it possible to rearrange the fields in the Purchasing/Inventory subtab -> Locations sublist on an inventory item form?

I'm about 90% sure you can't

Thanks, that’s surprising..

David- Might consider taking a look at the 'Advanced Item Location Configuration' feature. The feature includes multiple views and also allows for the creation of custom views. It does some other 'things' behind the scenes in terms of data structure, so I'd recommend doing some research/testing as well.