Through various bag addons I have seen different icons added over items in my bags. ElvUI adds item level numbers, and Pawn puts green arrows on items that are an upgrade to wear.
In the same way that I set up pricing schemes in my operations and groups, I'd be able to define criteria for bag highlighting on items. Based on auctionDB data and my defined pricing, a gold icon would show up on items in my bags currently selling at an agreeable price based on my settings.
For mule characters with banks full of BOEs and pets, it'd be awesome to quickly see what is worth pulling out of storage and listing.
Seems like a good default would just be no listings below minimum price, so you know you'd be listing the item if included in a post scan.