Hi Tom,
There is not currently any Artefactual-led development in this area confirmed to be on the roadmap, and I don't personally currently know of anyone who has shared local customizations adding a barcode field to the storage module. One thing I will say however that might make it easier for a developer to implement such a feature:
If you look at the two main database tables used in the physical storage module...
... then you can see that in the physical_object_i18n table, there is already an unused free-text description field. There's currently no corresponding field in the user interface, but one could be added. You'd still need to add the PHP code responsible for handling form submission, and more importantly, you would need to figure out how to add the new field to the search index - but it appears that no database schema migration would be needed to do so.
This is different than adding a dedicated barcode field AND a description, for example - probably a better long-term solution - but then again, there is a lot that could and should be done in the future to improve the storage module.
Regards,