The time I bult an unseen seer, I went human and used the human paragon class. Rogue 1/diviner 1/human paragon 3/unseen seer 10, losing only two caster levels. I realize your build as stated only loses one, but can you actually meet the skill requirements with rogue 1/wizard 4? Hide, Move Silently, and Spot are all cross-class; you can't put 8 ranks into each of them that way.