I had this idea that I thought would be pretty awesome, but its hard for me to explain. I'm going to do my best though, because if it is possible, it could really expand your idea. I'd also like to forward this by saying that I don't claim to be a programmer, and I don't even know if something like this would be possible:
Ok.
Most people that make rpgs specialize in one are or another, be it music, concept art, spriting, whatever. So in RMRK Universe, there's a hub town, I'm assuming. I think it would be great if you had a stretch of buildings, a bit similar to the sections that previously comprised the "Creativity Outlet." (Forgive my crude ASCII drawings)
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| building | | building |
| 1 | | 2 |
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| | | |
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road
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| | | |
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| building | | building |
| 3 | | 4 |
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and so on, and so forth.
Now the beautiful part comes in. Each building could be a "den" of sorts for each specific type of duty a person classifies themselves as. For instance, one could be "The Staff", which is where the composers can hang out and chat.
That's just the beginning though. Inside, you could have sort of a "Registration" that you do, where a person can upload a few of their works for others to sample. Like the registration at an inn. These could be sorted out by quality, and rated (by some sort of simple scale, eg. 1 - 10, 5 stars, etc.) by other people in the RMRK Universe! This way, a person looking for a composer merely strolls over to "The Staff", checks the registry, hears something that he/she might want to use, and then finds the composer in the Universe, or leaves them a message.
Also, to compliment this, aside from having an actual rpg class, like "mage", they could also have a real-world class, like "scenery artist".
This might make an extra step in the search for quality resources, but this way you are having fun in-game-world, while also building connections in real-world. I think this is probably the type of goal you had in mind when you thought of RMRKU.
I hope this helps, and is even feasible. If so, it would be a great boon to the Rpg making scene.