I'm glad you asked, HH. I'm thinking of making 23 placeable models, each within the size of the original skybox. As time progresses, I'll spawn another hour and delete the previous hour.
As far as the models themselves go, I'll be making each one a little smaller than the previous, to avoid clipping.
Now to address how the time thing goes.
In the module.ifo file, there are four fields of note: Mod_StartHour, Mod_StartDay, Mod_StartYear, and Mod_MinPerHour.
The first three are pretty obvious. The last is simply the number of Real-World minutes equals an Hour in-game. By default, the game modules operate on a 2 minute scale, meaning two real minutes is an hour in-game.
There's also a few functions of note: GetTimeHour, GetTimeMinute, and GetTimeSecond, and SetTime.
These return integers, which I can then convert to strings, add together, and set as a global string for the planet in general. I'll edit the OnExit script for each planet's module to set the global string. I can then add to the OnEnter script to get the last planetary time and set the current time to that, as I think the Mod_Start time is used upon load.
In this way, I should be able to do it, and I'll be adding up to 8 global strings, depending on Sleheyron's completion.