Mrdi, do you need visiblity as in being able to continuously see the time, or visibility as in being able to locate the clock in the dark, or perhaps both?
If you need to be able to see the time in the dark, then you might consider a Luminox alarm clock. It has Tritium lighted hands and number markers. Tritium lighting glows continuously for many years without any batteries or other external power source. No buttons to push, just a nice cool looking steady green glow. Of course you would also be able to locate the clock in the dark since it glows continuosly.
If you need the visibility in order to locate the clock in the dark but don't need to be able to continuosuly see the time, then you might consider one of the models from Oregon Scientific. They have a few models in their product line that have a flashing LED that enables you to locate the clock in the dark. Works just like the "Night Beacon" locator in the Eternalight.