1. My first idea is being able to become a bandit/highwayman. Join up at a bandit camp and kill oncoming travelers for their items and gold or become a highwayman and simply demand it from them. Either way this would add a much more evil way to make money and it would be interesting with enemies you would fight or how the people would respond to you demanding their money. Becoming a bandit would be considerably more dangerous than becoming a Highwayman though as it would be guaranteed that you would have to fight someone.
2. Possibly my favorite mod I downloaded for Oblivion was "Crowded Roads". This added many more people traveling the roads from smugglers to traveling adventurers. It really added a sense of immersion and many times you would be able to have someone help you in a fight. This mod also seemed to add more enemies on the edges of the roads so you almost needed to stop at an inn. It really made traveling much more fun to me.
3. My 3rd idea was the ability to make drinks, not just potions. For example using graqes or other fruits you could create wine. This wine would have different effects and when you "stored" it in a wine cellar, the magnitude and duration of the effects or the value of the wine went up. With this wine you could either drink it or sell it for a profit. These values would go up for every day/week/month of game days it was stored. This would also add a better incentive to buy a house with a wine cellar. You could store your wine and get a profit. With other drinks such as mead you could become a leader of a mead hall and create your own mead! Or you could make other drinks such as beer and use this and other drinks to stock a local inn. You could make some juice from different fruits which you could sell anywhere as well. The possibilities are endless.
4. My forth idea is being able to run a farm or tend to a garden. You could plant "seeds" and when a certain amount of time has passed you could get crops like you see in a farmers field. You could make different things out of these crops or sell them raw to a local store.
5. My fifth idea is becoming the leader or count of a town/stronghold/city/city state and run it. This would create income based on your decisions and you would live in the main building/castle/hall. To get there however you would either have to build the place from scratch similar to the Raven Rock colony questline in Bloodmoon or go through a election or something similar.
I hope you can add to my ideas and be saure to vote in the poll.