A very different solution -- If you're willing to do a bit of extra laundry, I very very highly recommend fuzzybunz. Their a brand of cloth pocket diapers that come with super absorbant microfiber towels to stuff them with (get the large towels) and if that's not absorbant enough, you can get extra towels and put 2 in. We loved them. They go on as easily as disposables, and if you're only using them at night they'll be easy to wash because it will almost always be only pee in them.
You can see them/order them at zannadu.com. They're a bit expensive at $18 each, but then again, they pay for themselves in a couple of weeks through all the disposables you don't buy.