so here's a question-- is there any published material for SOP that can allow someone to pick more talents if they pick them at a downgraded level, IE, a high caster getting two, rather than one talent if those talents are calculated as a midcaster? In other words, jack of all trades, master of none? I was thinking of working on something like this, but I don't want to duplicate it if it's already been published somewhere.
I am pretty sure nothing like that exists. Do be careful with this kind of effect however, as some Spheres don't care much about caster level (Life Sphere scales almost purely by the number of talents taken, and several of the good Divination and Fate sphere talents have the same effect regardless of caster level).
There is nothing like this.
I would also advise caution with such a mechanic. As Lirya says, caster level does not affect all talents equally. Warp can also be a great investment even without caster level, and there are some Time effects that are still amazing as well.
In addition, remembering what caster level different effects have could be difficult. While there are features that raise caster level for specific spheres, or other categories of talents, these all apply to an easily distinguished, thematic set.
If you did want to try and make something like this, my advice would be to make it a class, prestige class, or archetype. Rather than changing caster level for specific talents, have an entire class with the shtick of "not great caster level, but plenty of talents."