Okay, two things really strike me:
First, cheesy builds are encouraged? Then everyone's been going about entry into MT all wrong. Sorc 1/Cloistered Cleric 3 will do it, with Precocious Apprentice eating up a 1st-level slot but providing +2 to spellcraft checks and an additional 2nd-level slot and known 2nd-level spell. At 5th, you would be a Metamagic Sorc 1/CC 3/MT 1. What 2nd-level spell should you choose? Blinding color surge - it's both personal invisibility and blindness wrapped up into one nice spell.
Cloistered Cleric gives you three domains (one of which is fixed), a boost to skill points, and some extra spells on top of the normal cleric list. Your BAB will suffer by 1, but it's worth it. Once you get some heavy progression into MT, you'll be unlikely to run out of spell slots. Thus, you can afford to take Planar Binding, and burn all your 6th-level slots repeatedly calling up elementals.
Yes, elementals. I second Jack Smith's assessment of Planar Binding as a sorc's best friend, only I don't believe in calling up monsters based on the situation - just call up dozens and dozens of elementals, every day. Don't bother paying them anything; as a sorc, your charisma will be sufficient to force them to agree to your terms. One planar binding can call up three elementals, which can be made to serve as an open-ended task for a number of days equal to caster level (the DM may require a specific task - "Guard me for X days" works, as does "follow me and attack my enemies for X days.") Thus it is a simple matter to have a personal standing army of elementals. For variety, you can occasionally call a large elemental.
Individually, they don't pack much of a punch, but you should win by sheer numbers.