3.P - Adding Others' CLs to Your Own?

[MaxiDuRaritry]

I know about Circle Magic, from the Red Wizard of Thay and Hathran PrCs, but that seems a bit limited, especially given the PrCs don't work for the vast majority of characters.

Is there a way to add another's (or multiple others') CLs to your own in some other manner?

I know that psionic manifesters can manifest from another's powers known (so long as you share the powers on your power lists), but what about MLs? I also know about ultimate magus, spellthief and Master Spellthief, and the Psiotheurgist feat to add your CLs (or MLs) to your other CLs (or MLs) within your own build, but none of that is what I'm wanting. Thought I'd say that before anyone brought it up, just in case.

Basically, you have a minion or party member that adds its CL to yours to determine your spells' power, even if it means said minion or party member can't actively cast their own spells.

Anything like that floating around that I missed?

[edit] The fusion psionic power won't work, since your MLs overlap, although if you're a psithief (with the psionic version of Master Spellthief) and you use fusion with a psychic warrior or psion, you might, maybe be able to use that the way I'm wanting, although I'm not sure if fusion's caveat overrides that or not.

[Eurus]

Hmm, there are multiple ways for one character to give another character some kind of CL boost, but I don't know of any way to literally add your entire CL (or a percentage thereof) to someone else's.

The closest I can think of is maybe doing something strange with Mental Pinnacle? If you have a way to cast it on another character, and that character has Psiotheurgist or a psionic Master Spellthief...

[Prime32]

An 8th level kensai can use Instill to transfer some of their BAB and/or save bonuses to a 5th level abjurant champion, who uses their BAB as their caster level.

There's another source of circle magic in Shining South, with the Halruuan Adept feat and Halruuan Elder PrC.

Incantatrix can apply metamagic feats to an ally's spell as they cast it.
There's also the Cooperative Spell feat for boosting CL checks and save DCs when multiple characters apply it to the same spell on the same round.

There are rules for lending a legacy weapon to an ally, which can contain abilities that apply free metamagic to your spells.