There is a technique I have used in the past that uses channels as categories. Its pretty niffty as you can have any fields you like in the categories section.
• Create a channel called categories (Or whatever)
• Create a channel that you want to categorize (say, products)
• In the 'products' channel, add a Playa or native relationship FT to it that only looks at the 'categories' channel.
You can then use that relationship field display your entries for that cat. You can also create a better URL structure for SEO this way, and go to town on the categories fields.
It can be a bit of a pain getting your head around, but it is really powerful.
The whole native EE cats really need a good going over in my mind as they are quite limiting compared to teh rest of EE. I believe there are some new category hooks in 2.7, so fingers crossed a dev will take up the challenge.
As far as your question goes, I don't think there is anything available at the mo. I'll try and think of another way round, but the above is potentially a good way to go.
Hope it helps