As ponyus said, it may be that it’s something to practice their skills on. I’ve done a few GIMP scripts to automate some of the tutorials I’ve seen because they looked neat and I can certainly use the practice in the script-fu language!!
It might also be something very simple, or something that they’ve already worked on. One person was asking on how to make “rhumb lines” on a map. I had written a script that did something similar to that, so after a couple of very quick mods to my script, I posted it. On the GIMP registry page, someone posted a script to turn a flat 2-D picture into an isometric view. I had written a script to make a generic brick wall, so I went ahead and posted that right afterward, since they went very well together. (I also got some really good feedback on how to improve it, which I put into the next version of the script.)
Obviously, you’ll get more bites for a paid request, but there is still a bunch of really good work out there.