If we need a Divine caster, I am in the process of finding out if a build of Gynosphinx5, Ur-Priest1 would, in fact, grant casting amounting to (with bonus spells):
Lv
3: 2
4: 2
5: 2
6: 1
Hey CNC, what are you considering? Hit me with the whole list! lol.
You sure about that?
Other than the above silliness, which I'm not really expecting to pass muster with Oslecamo or you, the condensed list in no particular order:
A spellshaper. Possibly a Monster Class 3 or 5, Spellshaper 3 or 1 if I can get the "treat levels in this class as levels in an arcane class" ability to grant full Shaper level. Mindflayer5, Impulse Mage1 is the build I've put the most thought into so far but there are at least half a dozen potential shaping based builds kicking around in my head.
Similar to the above Monster Class plan but with a published casting class. Beholder5,Wizard(focused conjurer)1 would cover the party's utility casting needs pretty well.
A Historian (Past,Present,Future): I love the idea of this class and I have a fun concept involving a Neandertal and much Temporal Hijinks but I'm loathe to bug you to finish the port since I'm sure you're plenty busy right now. I'm also not sure I have the time and energy myself to invest in coming up with a full Historian build.
A martial adept: homebrew either in class, discipline, or both. I had the zany idea of a Choker2,Hylian Warrior4 a week or so back and it undeniably tickles me (when I picture a choker in a little green Link hat trying to rescue horrified princesses, I giggle) but there's already a Choker in the game and I don't want to be derivative.
Residuum: probably either Spellknight or Priest of Legacies. Not sure where I'd go with this one but i like the system.
A Ritual user: I need to get a firmer handle on the ritual system but I read the Augury campaign thread and Garryl's Ritualist was able to do all sorts of fun things at only lv2. Something rituallish could fill the caster niche and be fun and interesting.
And I'm sure there are other ideas lurking in the back of my brain ready to pounce as soon as I start to settle on something.