Hmm... I made some bricks that would automatically set to unrendering upon being planted. But I don't remember if they flashed. I stole the script from the ZoneBricks addon. So maybe you could check and see if if those giant zonecubes flash upon being placed.
Edit: I just realized who you are/what you're working on. If you can't make the 2x2f not flash, I could make you a brick without any visible meshes. Maybe that wouldn't flash.
