I dabbled into the particle editor, and after spending a couple of hours getting used to it and trying things out, made the first spell effect.
Found out that it's pretty easy to make pretty good looking random shaped clouds in the editor, in addition to everything else that's possible. I'm open to specific requests for effects and am happy to help anyone getting around using the editor (even though I'm still only learning myself). I'm not going to be creating my own mod, so these effects won't be included in the game unless someone wants to pick them up and use them in their own mods.
Here's the first version of the first effect, Thunder Strike:
http://www.youtube.com/watch?v=kbceNBqC0s4
Corrupt Elements:
http://www.youtube.com/watch?v=WQWJp2-J-rE
All effects (XML files) will be available to download from here:
http://linque.pp.fi/Elemental/Effects/