Have any of you used alternative items in place of the typical plastic litter box? I'm very interested in discovering a more attractive way, that both my cat and I can live with, of holding the litter. So far some of my ideas have been... a large galvanized tub or a large enamelware pan. Will these two ideas be too slippery? http://www.thecatsite.com/forums/new...newthread&f=6#