Just went looking through the addon category of
Bags, Bank, Inventory
First one I came across was
BagSync . Sounds like it will do exactly what you are looking for.
BagnonForever May do what you want as well. You'll find it bundled with the excellent Bagnon addon.
Something to keep in mind also... Memory usage isn't
that large of an issue. If I understand how these particular addons work, all they do is keep a database of collected information which creates static memory. The more items and characters that you have stored in it, the larger the database no matter which addon is being used.
The performance hit will only come when you begin to mouseover items to see the counts. That's when it's up to your CPU to do the work of finding the info in the databases. And even then, the hit from an addon like this would/should be so insignificant as to not really matter which you used. It would all boil down to which you preferred.
Linear Mode
