Considering a Druid/Thurmaturgist, I just need that spell...

[RUMBLETiGER]

entirely by RAW, there is a simpler and less obscure method to be able to cast a 4th level spell. Any spell up to 5th level. A simple ring of spellstoring would do the trick, by RAW they allow the wearer to cast the spell stored. Just ask someone else to cast lesser planar ally into it. Disadvantage is that you have to keep it on and filled, or you'll lose your thaumaturgist abilities.

Never heard of this as a legal option, but sounds legal at face value. I could see a DM shooting this down, but it works mechanically.

 

[RangerWickett]

Win with semantics.

Ask your GM if he minds you reflavoring your spells with custom names. "Flaming sphere" becomes "burning tumbleweed," and "entangle" becomes "gang of pixies using vines as lassos." Once he approves all your primary changes, just casually mention next session that you're casting, "Lesser Planar Ally," which is what you've renamed your Summon Nature's Ally 4 spell.

 

[RUMBLETiGER]

Win with semantics.

Ask your GM if he minds you reflavoring your spells with custom names. "Flaming sphere" becomes "burning tumbleweed," and "entangle" becomes "gang of pixies using vines as lassos." Once he approves all your primary changes, just casually mention next session that you're casting, "Lesser Planar Ally," which is what you've renamed your Summon Nature's Ally 4 spell.

That's sure to get something thrown at me. But, if I were to do this, I'd rename a level 1 spell instead.

I think as a result of having the conversation in this thread I'm learning the lesson, "Don't try to take the Druid and make it even more powerful".

 

[Jackinthegreen]

I think as a result of having the conversation in this thread I'm learning the lesson, "Don't try to take the Druid and make it even more powerful".

Who needs oddball rules to do that when there's the Planar Shepard? lol

 

[RUMBLETiGER]

I think I've found my solution, but it's odd.

I discovered the Pathfinder PrC Arcane Savant.

Despite the class name, there's no "Arcane" requirement to the PrC. The requirements are as follows:
Feats: Magical Aptitude, any one item creation feat.
Skills: Knowledge (arcana) 5 ranks, Spellcraft 5 ranks, Use Magic Device 5 ranks.
Special: Ability to cast 2nd-level spells.

The level 2 ability, Esoteric Magic, allows for learning a spell off any spellcaster's list. If it's from another list, treat it as 1 level higher.

This means, if I wanted to use this class to enter Thurmaturgist, I'd need to consider Lesser Planar Ally a 5th level spell. Since the PrC loses 1 level of spell progression, I'd need to be a Druid 8/Arcane Savant 2 in order to pick up Lesser Planar Ally.
I think I'll approach my DM with this build concept and see if he'll buy it.