Yeah, it's huge, I don't think I realized how big it was. I got the box at my door and was like.. whoa... this is going on a 29g! Oh well, it's the exact size of the tank so the light is pretty even on the whole tank. I guess that's kinda nice... Still doesn't look like your would work... I don't think it goes back far enough to clear the light.
Might have to go with a prizm or something crappy with 3" clearance on top. It would be better than running nothing I'm sure.