Been going through the books for the first time in years :P The idea is to combine sneak attack and stuff like earth glide, aswell as being a very versatile character in general. came up with something like this:
1 spellthief1: Able Learner, Craven
2 wizard1: Scribe Scroll
3 wizard2: Earth Sense
6 unseen seer1: Master Spellthief
7 unseen seer2: Silent Spell, Advanced Knowledge (Hunter's Eye, Rgr 2, PHB2)
8 earth dreamer1:
9 earth dreamer2: Practiced Spellcaster (Wizard)
10 earth dreamer3:
11 earth dreamer4:
12 earth dreamer5: Heighten Spell
13 wizard 5: Earth Spell
2d6+4d6 (Hunter's Eye) sneak attack
Spell Stealing up to 4th level spells
Cast spells in light armor
But im not sure how to continue, arcane trickster? must be a better choice out there?
im not set on feat either, im not sure any of the feats exept for the required ones are really worth it.
Some equipment worthy of note:
Bracers of the Hunter (Secrets of Xen'drik, 8,500 gp) +5 competence bonus on Hide checks, +2 competence bonus on initiative checks and +1d6 damage to sneak attack or sudden strike.
Circlet of Rapid Casting MIC, Head, 15.000: Sort of rod of quicken, but with some modifications and nearly half the price.
Belt of Battle MIC, Waist, 12.000: It will help you cast a full-round action spell and move, or quicken a spell, or even cast two full-round action spells in a single round. As an icing on the cake you get a +2 competence bonus to your initiative checks, which is great for wizards anyway.
Rogue's Vest MIC, Torso, 18.000: Gain minor bonuses to move silently and hide and a competence bonus to reflex saves. Additionally boost your sneak attack or similar ability by 1d6.