The blockchain can support this since hard fork 17 even though the interface does not yet. It's a real pity, no one is really talking about it any more, but for example the eSteem app takes a 5% cut every time you post through it. See here for example (note that percentage 500 is 5%)
I'm working on a small single purpose app here which is not done yet but when it is you'll be able to do exactly as you say here. Though ideally it would be available through steemit.com
That is awesome! Thanks again for your hard work and dedication to Steemit.