In answering the "waterproof" question there are three sources of water to consider: precipitation, condensation, and seepage from underneath. Any decent tent should handle the first easily because it's just not that hard to keep raindrops out. The second two are harder. Condensation, and preventing it, is a whole topic in and of itself involving temperature and moisture differentials and circulation. Seepage is a problem because water runs under the tent during a big rain and the pressure of your body can cause the water to permeate the floor material. Again it's hard to avoid this. Good site selection can help but even that is not foolproof. If you get condensation or seepage it's not necessarily the fault of the tent.

The question may really be "is there a rainproof system of any kind?".

I'll tell you the best solution I've ever found. My daughter and I were out camping on a night with record-breaking rain. It rained hard all night. The ground all around turned to a bog with small ponds in low-lying areas. Creeks and rivers rose above flood stage. Something in excess of 6 inches of rain fell while we were sleeping. But we stayed dry all night. How is this possible? Well it turns out we were trying out our new hammocks (one homemade and one Hennessy). Both had silnylon tarps over them so there was no worry about getting wet from precipitation. In addition tarps allow unimpeded circulation so condensation is almost a non-issue. But even if it does occur it doesn't get you or your bag wet because it runs down the inside of the tarp and falls on the ground. Finally we were not on the ground so seepage was impossible (and believe me it would have been a huge issue that night using any tent or even tarp/bivy).

That sort of made me a hammock convert. They aren't perfect for every situation. In particular in cold weather you get colder if you are suspended in mid-air. But if the question is staying dry then it's hard to beat a hammock and a tarp.