Well, think about the logistics of this. Assuming a tomato plant is kept for three pickings and highest yield. If you can grow year round you can get 3 or four cycles in. Yield will depend on variety and type. Determinate plants will produce most of the tomatoes all at once and indeterminates will produce a few over time. Caging and trellising produces more tomatoes than staking but staked tomatoes can be larger and heavier. Tomatoes get 8 feet tall so you would need room for the pot and the plants to grow vertically. Say you went with the heavier tomatoes like super beefsteak, Brandywine, Pruden's Purple, Cherokee Purple, Big Beef, and a few cherry tomatoes like Sunsugar and a current like red current. The smaller tomatoes will give you the most number of fruit. As fruit size gets bigger, numbers actually fall. I have gotten anywhere from 8 to 20 lbs of tomatoes from a single plant in any one picking. My plants are in full sun and I have a long growing season.
In a room you will be limited by the number of plants you can accomodate in the space. Most places recommend compact varieties which will not get a lot of yield but take up less space and are suitable for containers. New Big Dwarf is a possibility. It has large tomatoes on a compact plant and Husky is a determinant cherry.. Recommended were patio, toy boy, pixie, and tiny Tim. Threse tomatoes are unlikely to get a considerable yield in winter. In the summer months you will get better results planting outside or in a greenhouse to extend the season.
You will need to provide not only the buckets, water, support system (trellis), temperature control, but also light for the plants and some way to circulate air. If you cannot provide the environment especially light and temperature control the tomatoes won't make a lot of fruit.
It will be heavy and you will need to make sure your attic is designed to take the weight. Most people use a basement instead if they have one. If you have a leak it will drip through the ceiling of the rooms below.