I know there is some super hi tech luminescent stuff. That's what I'd like to use. Barring that, what other stuff could I use? I don't want some cheap glow in the dark paint.
Phosphorescent paint can only store enough energy for a few hours. To last longer, a source of energy is needed. Years ago, before the dangers of radiation were realized, radium or other radioactive material (e.g. tritium in a sealed container) was used to power radioluminescent paint.
A more practical design, today, would be to use a UV LED or small argon glow lamp (AR-2 or the "starter" for a fluorescent light) to excite he luminous paint. This would also give you control of the brightness by changing the series dropping resistors.
Since it is a wall clock, you could also consider adding active lights to it. If you add a few leds or a small led strip you'll surely have no problem seeing the time.
You could either opt for illuminating the background adding lights to the rim of the clock, or the faces as well if adding lights slightly in front of the clock.
The really cool version would however be to replace the back with something semi-transparent, and put the lights behind the new back. Thusly making it backlit.