I've always used the standard flour+water = paper mache. This often results in a somewhat heavy and fragile object though.
I'm looking for a formula for a strong but light weight version. Light-weight being key. I'm hoping to create a scaffold of chicken-wire and mache over it to create a smooth surface. I've also read that using "blue shop towels" can be better than newspaper so that is what I'll do.
The end product will be moisture-sealed and mounted to the bathroom wall to hold toilet paper in a decorative way (think "giant sheep" or some other fun shape that involves toilet paper rolls).