PMMI still mades and sells a clock that is generic that should be about the right size. Instead of saying Time and having the Newell logo, it says Alarm Clock and has no logo.
Click here for details. Don't know the price but $200-300 would not surprise me.
You might be able to find a digital clock display at an electronics store and mount it on a piece of smoked or black plexiglass cut to the size to fill the hole and save hundreds of dollars.