IF I wanted to do this, and I don't because I certainly don't need to look at a device int he shower, but IF I were to do this, it would be using a second monitor. You try to extend those laptop cables and you'll find out real quick it can't and won't work very well because it will have zero in-line noise filtering.
I'd buy a touch screen monitor, and you can buy longer length VGA and DVI cables, and connect to it that way. You may even get off with a touch screen by doing that. If your laptop only has a VGA out, I would check for operation with a VGA to DVI converter.
Even LCD's get warm though. They need air as well. Otherwise, it will form moisture even if it is embedded in acrylic and water proofed. You may be able to stick some of those moisture soaking bags in there to get rid of the initial levels of moisture though. After that, it shouldn't fog up from the inside.
And that's why we have him around! Having a fan, even a small one, would solve the problem, and you could use a pressure valve to keep moisture out. A half-baked idea, but whatever...