[General Discussion] If technology was no object, what game would you make?

I've often thought of something that combines:

A full spaceflight engine, complete with stats and upgradable ships and parts (a la EVE, Escape Velocity, or Elite).

A fully-realized on-the-ground engine for walking around, with equippable items and RPG-style stats (sort of like Mass Effect).

Combine both in a setting (maybe a solar system but ideally a galaxy) where hundreds of planets and other objects are rendered so you can do everything from fight in orbit to explore the surface on foot. Add an overarching story along with sidequests and such (an asteroid mining minigame, perhaps?) and maybe even online co-op.

Parts of something like that have been realized in various games, but combining them together on an epic scale would take a huge amount of memory and processing muscle. Still, I'd kill to see something of that ilk (especially if it's not an MMORPG).

Jam it back in, in the dark.