I'll take a look at geomancer, it sounds like it has potentail although its a bit of an oddball in a dualcaster handbook.
Snakeman- How does the Shadowcaster build work exactly? I'm not clear on how Mystic Theurge is advanceing shadowcaster, but I could have missed something since I pretty much wrote them off a sucking, but another dual 9s build that doesn't rely on UrPriest/Divine Crusader is always worth noting.
Prime- I'm strongly of the opinion hat Precocious Apprentice dos not allow for early entry, to the point that I don't even intend to present it as an option. If it actually granted the ability to cast 2nd level spells,it would ignore its own limitation since you would be 'casting 2nd level spells' already.
Anywho, since no one has come forward saying they know of a guide like this, and there certainly seems to be enough interest in one, I'm going to go ahead and do this.