Some cheesy ways from earlier threads about this topic:
3 Levels in arcane class, 1 level in divine class. With the investment of one feat and one trait (Magical Lineage and Heighten Spell) you can select a 1st level spell from your divine class, Heighten it to level 2, and then reduce the spell slot cost back to level 1. This fulfills the requirement and allows entry to MT at level 5.
Alternately, you take 1 arcane level, 1 divine, then select a spell on both lists for Magical Lineage. This allows entry to MT at level 3.
Also the wording for Candle of Invocation seems pretty promising for the the same reason. Read "spells normally unavailable" below.
Candle of Invocation
Aura strong conjuration; CL 17th
Slot none; Price 8,400 gp; Weight 1/2 lb.
Description
...
A cleric whose alignment matches the candle's operates as if two levels higher for purposes of determining spells per day if he burns the candle during or just prior to his spell preparation time. He can even cast spells normally unavailable to him as if he were of that higher level, but only so long as the candle continues to burn.
In addition, burning a candle also allows the owner to cast a gate spell, the respondent being of the same alignment as the candle, but the taper is immediately consumed in the process.