Last night on IRC we were discussing good models for multimaterial...something more interesting than a 20mm cube. I pulled this Tux model from the google warehouse (http://sketchup.google.com/3dwarehouse/details?mid=ae5539bc0cf3c63cee8ad7957b96e8ae&prevstart=0). It is scaled to a reasonable size and could be used to experiment with support material (the butt and the arms) or two tone printing (belly and body). If I have time I might take it further (i.e splitting it so that it could be done as a multicolor print).