[dmm]

Nice idea. I think they should all have to be on your homeworld. No fair putting the Emperor's Palace on some junky moon. And of course he's going to want to surround himself with the main Intel and Research compounds. Adds some extra "ouch! factor" if you have to use up space on one of your best planets.

I hope you don't mind a bit of criticism, though. Why should a palace make anyone but the emperor happier? Maybe more productive and/or less likely to rebel (because they are cowed by the emperor's wealth and power). On the other hand, a palace might make discontents even more likely to rebel. Hard to say. Maybe a palace should do nothing, except be a prerequisite for the other empire-wide facilities?

Some other suggestions:
Institute of Mining -- would increase mining output. Same for organics and radioactives.
Institute of Health -- would increase reproduction. (And maybe decrease industrial output?)
Institute of Arts -- would increase happiness levels.
Institute of War -- would increase offensive and defensive bonuses, or maybe physical strength.

Maybe not all should be available to all race demeanors, e.g., peaceful races couldn't build an Inst. of War., or warlike races couldn't build an Inst. of Arts.