No offense, Jes, but I don't think the Brickcount is the real concern (though most people claim it is). I have noticed that if I have more BRICKS, but fewer visible rendering FACES, I will lag less. This has too many faces on it that are rendered no matter what. When I make crate piles, I tend to "fill in" certain inside sections to reduce lag. Even if we could "fill in" the side parts here, it wouldn't help because those are omni quads.
That being said, I remember a version of Minifig V2 that when placed would essentially "plant a macro" for the entire minifig. Perhaps if you went that route instead and made this as a timesaver rather than a brickcount-saver-that-lags-me...