Here's a cleaner version that doesn't require a pile of shuriken:
Feats: Inevitable Accuracy, Grazing Shot
Powers: Martial Supremacy, Inevitable Shot
Items: +1 Tratnyr (or Drow Long Knife or Net for shorter range)
For this version, you just keep using ranged basic attacks (with a heavy thrown weapon) and missing. Every time you miss, you deal Dex damage (from Grazing Shot), refresh Inevitable Shot (from Inevitable Accuracy), and use Inevitable Shot again. If you ever hit, you can reroll it with Martial Supremacy.
At level 30, if you started with 8 strength, you'd be at only a +14 to hit vs. AC (1/2 level + 1 enhancement - 2 range), which should miss everything except on a 20, and you can reroll 20's with Martial Supremacy. You can also add in some encounter or daily rerolls (e.g. elven accuracy) in case you get two 20's in a row.
You don't even need to be a seeker or hybrid seeker for this -- you can do it purely through multiclassing. If you never hit, you never expend Inevitable Shot, so having it as a daily is fine. To add this to any class, you'd use:
Bardic Dilettante
Multiclass Mastery (gaining Primal Sharpshooter and Brawling Warrior)
Acolyte Power (swap for Martial Supremacy)
Inevitable Accuracy
Grazing Shot
The only prerequisites are 13 Cha and 13 Wis, plus some Dex so Grazing Shot deals damage.