Have you tried the pee pad trays? They contain the leaks and spill-overs well. My dogs are weird and would not pee on the pad when I put it in the tray but I still thought it was a great idea!
Better pads could also solve the problem -- RBD911 sells a good quality pad that does not leak, unless the pup pees right on the edge -- no help for that.
He also sells teh washable pads that are even better at being leak-proof. Here is a link to one of his threads:
http://www.yorkietalk.com/forums/yor...-shipping.html
BTW he sells the pee pad holders/trays too!