I off and on use a shortened form of the Bornless, not unlike the one in NAP.
Tho, to be honest, I mostly consider it a nice bit of verbal badassery that puffs the magician up to feel all-powerful, not necessarily crucial to the working.
Sort of like magic's version of "I am the one who knocks" ...
So, I think you can substitute about anything that makes you enflamed with power. For a different spin on the same idea, I've used the "Song of Amergin" (Amergin was the druid brought along with the Milesians when they invaded Ireland and defeated the Tuatha DaDanaan, the semi-mythological race of elves then ruling Ireland.)
"I am the wind that blows upon the sea;
I am the ocean wave;
I am the murmur of the surges;
I am seven battalions;
I am a strong bull;
I am an eagle on a rock;
I am a ray of the sun;
I am the most beautiful of herbs;
I am a courageous wild boar;
I am a salmon in the water;
I am a lake upon the plain;
I am a cunning artist;
I am a gigantic, sword-wielding champion;
I can shift my shape like a god."
It's a bit of a different head than the Bornless, but quite interesting in its effects.