hey,

I bleached a few leaves on a plant earlier by putting it too close to a 400 watt mh... the two leaves went white, i moved the light higher and it recovered well, so just keep an eye on it...

I think that you might worry more about becoming inefficient. that much light in that small an area will grow some big dank buds, but is it worth the extra cost in electricity? Its not cheap and you can still pull down some great weight with less... you definately have some diminishing on yeild per watt, if you size down to a small space. I am not certain about this, but I imagine that at some point, the size of the root structure, and the levels of c02 could become factors limiting the ability of your plants to actually use all that light.

do you have room to expand?