I use this method and have found it to be a good way to deal with:
1.having to throw away litter boxes every few months because of smell permiating through plastic
2.finding a box tall enough or one that has the right kind of cover to accomodate my boy kitty who pees standing, not squatting
3. needing multiple boxes
I buy rubbermaid type plastic tubs when they go on sale (esp. the red/green or black/orange after holidays) and either cut a hole (with a small hand held electric saw thingy) big enough for my kitty to fit through about 3 inches from where the top of the litter would be or let them jump in from the top (and put a stool for them to jump on). I have now a tub that is about 2.5 feet long and is great for more than one kitty. I use the clearish type tubs, but if your kitty likes more privacy one could use a solid colored tub. You can choose whether or not to use the lid for more odor control, but have to consider the height of the tub so kitty can stand comfortably. One could also stack one tub on top of the other to have multiple boxes in a small space (just have to have the bottom one with a hole and the lid left on). I have often seen these tubs at yard sales very cheap.
...wanted to share
