Trough Garden

Does anyone know a good source for, or know how to make, an "artificial" stone trough? It would need to be substantial and not a styrofoam box painted grey. There is a way using cement, peat and sand but I'm not sure of the proportions or the technique used to impart an authentic stone look. That's why I'd rather buy one that has been formed in a mold by someone more artistic than I. I've been wanting a trough garden (or three) with dwarf conifers, saxifrages, etc for many years. Might even do some bonsai within the trough as well :>) Any help would sure be appreciated.