An idea for the original version in the first post: perhaps move the contemplative and dweomerkeeper levels up sooner, ultimately delaying the highest level spells, yes, but making it about 4 levels sooner that you can use supernatural spell on PaO, which if you have to worry about dispelling before then, is still quite good, methinks.

Another thing, a highly debatable thing, but still worth mentioning, is swapping a dweomerkeeper level (since supernatural spell is at 4th level, not 5th) for a level of Prestige Paladin, as Paladin of Tyranny, or Ur-Priest adaptation, and taking Sword of the Arcane order to get wizard spells on the Ur side as well as beholder mage side. I disclaim, however, that this is rather cheesy, and also debatable about whether it works, but just a thought.