I'm trying to find a way to add the spell Emergency Force Sphere to a Summoner's spell list. Without level dipping, does anyone know a method?
Play a samsaran. That's the only way I know of.
Mystic Past Life (Su) You can add spells from another spellcasting class to the spell list of your current spellcasting class. You add a number of spells equal to 1 + your spellcasting class's key ability score bonus (Wisdom for clerics, and so on). The spells must be the same type (arcane or divine) as the spellcasting class you're adding them to. For example, you could add divine power to your druid class spell list, but not to your wizard class spell list because divine power is a divine spell. These spells do not have to be spells you can cast as a 1st-level character. The number of spells granted by this ability is set at 1st level. Changes to your ability score do not change the number of spells gained. This racial trait replaces shards of the past.
Yep, that's about it. EFS is one of those spells that may get the GM throwing the book at you, though, so you may want to run it by them first.
...or spells from another list in general. EFS was what made me start looking.
Ring of Spell Knowledge would work for something lower-level, but this would be too high for type IV. You can get a cantrip added to your list with a trait. Other than those two options, everything requires levels in a different class/PrC. Well, that or mythic ranks.
Well you also have the spell research rules which i think is also in core, but its very up to the DM if they allow it. Technically its mostly up to the DM for custom spells and "X version of Y" spells is a check with some cash and time involved unless the DM says "no".