Reduce Create Magic Tatoo casting time?

[Story]

Is there any easy way to reduce the casting time of Create Magic Tatoo down to one full round or less? CMT is a 2nd level spell but it requires CL 13 for the useful tatoo. Elder Giant Magic gives you +3 CL for passing some concentration checks, but unfortunately, it can only be applied to spells with one round or less casting time.

[Randomguy]

Use shadow conjuration to mimic it and fail your will save to disbelieve so that you experience full effects. This also gets rid of the material component cost.

[JaronK]

Shadowcraft Mage of course does that the easiest, but anyone can do it of course. SCM does let you easily get your caster level up (when combined with Earth Spell). The other option involves making it a spell like ability... I believe Spell Stitching can get the job done there.

JaronK

[Darrin]

This one's a bit klunky:

Illumian Wizard 18.
Feats: Improved Krau Sigil (1), Still Spell (3), Silent Spell (5), Quicken Spell (6), Sanctum Spell (9), Alacritous Cogitation (10), Verstatile Spellcaster (12), Extra Slot (15).

At 15th level, you can bump your 8th level spells up to 11th level spells via Improved Krau Sigil + Sanctum Spell + Verstatile Spellcaster. So Extra Slot can give you a 10th level spell slot.

At 18th level, take Innate Spell to convert create magic tattoo into an at-will SLA. It will cost 500 GP in material components per use, but casting time will now be a standard action.

[Stegyre]

This one's a bit klunky:
I fear that it also moots the problem. If I'm reading the OP correctly, his aim is to be able to CMT with a CL 13 (so he can get the really good benefits). He has one option to gain +3 CL, but only if he can reduce the casting time.

Any proposed solution starting at CL 13 or higher . . . well, if the OP had that CL, he wouldn't have had the problem to start.

@OP: I have a vague recollection of a feat that does reduce casting times. I'll have to look through my notes for the name. I am not sure if it will get the casting time down as far as you need.

EDIT: I was thinking Rapid Spell (CDiv), and as feared, it would not take you far enough.

That said, there are many other ways to boost CL. Assuming you just need +3, you could use Bead of Karma (+4, must have a way to "cast" a divine spell); Spellgifted (trait, +1 CL for spells of one school, -1 CL for all other schools, but conjuration is a good school); Arcane Thesis (+2 CL); a friendly bar with Inspire Spellpower (RoS, +1 CL) or Harmonic Chorus (SpC, +2 CL).

There are several other CL-boosting options beyond these, too.