That's one of the players bigest concerns: Will Bethesda make expansion set, if mods bring them enough money (equal to profit of the exp set)? I certanly hope that they will start working on the expansion as soon as posible, because just like for you, regular Oblivion became boring for me.
On the bright side, we have a very strong modding community. There are mods that balance the game, improve GUI, add new creatures etc. There are even groups that are making big landmases, with new quests, weapons, storyline and all. You can call that a ''community expansion sets''

EDIT:
Silgrad Tower team being a good example
This post has been edited by HyPN0: May 17 2006, 09:20 PM