We've spent the last 2 days painting the interior walls. It's sort of a grayish/whitish/yellowish color. It looks like a space ship. OK, not really, but we did mixed in this fancy insulating powder that NASA developed. We still have a coat or two to go on the walls and we're going to paint the floor as well. Since it's for insulating purposes, rather than aesthetic, the color doesn't matter at this point and most of this won't be showing anyway. After we are done painting we'll be covering the walls with plywood and thin insulation then covering the whole thing with sheet metal to give it a high-tech feel.