We'd need to really play with this I think. The thing is, radius increases with the cube root of volume, so a million body points would be...

a bot with a radius of 600 (compared to a bot of 1000 body points with a radius of 60).

Large, but not inordintaley so.

A billion body points would be...

6000 radius. That would be as long across as 100 bots with 1000 body.

Big, but not terribly big considering the sheer number of body points it would have. I mean a billion? Holy cow.

And bigger bots would have a problem seeing, because presently the eye is assumed to be seeing from the center of the bot. Anything bigger than 12 robot lengths wouldn't be able to see I don't think.