I don't have Oblivion yet, but I plan on getting it (90% chance I will). I have no modding experience, but I've loved PSO for the longest time. I was thinking of making a mod for a game, and Oblivion came to mind. I plan on making 3-4 hours of story content and an aditional 5-6 hours of side-quest like content. I know I can't really make futuristic placement items, but I can reskin, which I'll use to my advantage. I will make weapons specific to this area! Including (but not limited to): Saber, Sword, Handgun (if possible), Dagger(s), Partisan, etc. For those who don't know, PSO is a futuristic RPG. For instance, the Saber is reminiscent of a lightsaber, and even if this is terribly hard to skin, I'll do my best. Photon Crystals (name pending) will be the exchangable item for the special items. I will try to have a new class or 2 (ex: Humar, Hunewearl from PSO) to go with it also. Photons will be obtainable by doing quests, killing enemies, trading, buying, etc. I will have new clothing also, that is if not exact, then reminiscent of PSO gear. If possible, I will make new enemies to go with it (from PSO). I will make a landmass that is (hopefully) only accessible by fast travel. It will be for high level players and new ones alike. Say you go there when you are level 5 and do all you can. You can continue the main story and come back at around level 10 and do more and so on and so forth. Most of the items (besides the best ones) will always be just as good as you can get in the main story, to prevent unbalancing the challenge of the game. You won't be able to get good items until later in the game. Also, I'll consider the planet Ragol being the moon.
Tips, add-ons, and constructive criticism would be greatly appreciated