My post will likely come across diffent from almost every other, so first I'll tell you why. I work cat rescue. And between the economy and annual 'kitten season' there are not enough homes. Cats and kittens both are being put to sleep all over the place due to poor planning and mismanagement.
Is one room ideal - no. Is one room ideal for a kitten even more of a no, could one room be perfect for a cat of say about 2 that has always lived indoors, has been given up by it's family and is likely to be put down because somebody wants a cute little, loud, rowdy, messy, misbehaved, yowly kitten.... yes yes yes! There is almost always a perfect cat for any given living situation. The question is are you willing to adjust your expectations and make the commitment to it lifelong once you find it?
Older cats live in one room in nursing homes happily with their older people often - kittens - nope. Then the older people die and leave cats behind with no one to love or care for them.... maybe a kitten isn't the best choice for you right now. maybe a middle aged or older cat is exactly what you need - not a medical disaster kitty - just a slower cuddlebug who likes to keep to one room, who is accustomed to it, and would become not only accustomed to but grateful for you as well.
we always have at least 2 or 3 cats like this whose owners have passed with our rescue I'm sure anywhere you check could point you in the right direction.....
In a few years when life is easier for you and your cash flow allows for more of your own space go for a kitten or better yet two & you and your then old friend can cuddle together and watch them tear the place up