One idea would be to be a flying, hasted, displaced halfling sorcerer wielding 9th-level wands of magic missile. You can easily get your AC into the low thirties and plop a 50% miss chance down on top of that; when hasted, you'll do an average of 35 points of damage per round, with only spell resistance to defend against it. Put 30K into the wands to get 200 charges, or get craft magic wand and put 15K into them.
Be the party's buffer: get cat's grace, fly, haste, endurance, improved invisibility, and similar spells.
Purchase several scrolls of cloudkill, and take wall of force as your 5th level spell. Use these two in rapid-fire combination to take out big non-spellcasting enemies: no save for the wall of force, and almost certain death for folks without teleportation magic.
Since you're a sorcerer, leverage that high charisma into a cohort cleric with a ridiculous CON who'll cast shield other on you. You should be able to afford a 9th-level cohort, and probably a couple of 2nd- and a third-level ally. Leave the first-levels behind; the second and third levels can be rear guard rogues with high spot, listen, and hide checks who'll carry gear for you.
Feats you'll want:
Dodge
Spellcasting Prodigy
Craft Wand (get these wands for cheap!)
Spells you'll want:
Dispel Magic
Fly
Haste
Solid Fog
Dimension Door
Wall of Force
Cat's Grace
Invisibility
Glitterdust
Rope Trick
Magic Missile
I've wanted to use this concept for awhile; I think he'd be fun to play, and deadly in an arena.
Daniel