In the Arch AUR there are not just ebuilds for software but for themes, editor customisations and other small snippets of things which could be useful to other people.
For example, rightly or wrongly, the first thing I look for when installing any Linux Distro is how quickly and easily I can pimp my desktop exactly to my liking. Its important that my desktop is more cool than anybody elses:):) The AUR repository is an excellent resource of users customisations to help me a achieve that.
Now, I've customised my desktop I say to myself, I wouldn't mind a bit of fame, let's customise the original theme ebuild a bit and submit it to see if people like it. Now I feel even better (as long as I get some votes:)).
This can be done via forums to begin with but it really needs more structure. For example, you'll want an overall summary page with a proper query section to see what is available and the vote ranking.
While you are correct in saying a lot of people wouldn't care to write an ebuild, the Arch community at the same time shows that a lot of people would be interested in contributing something back. It also empowers people. Even if they just submitted an ebuild containing a few icons they feel good seeing it there. Lastly, something like this wouldn't be much work to implement.