I've got a couple of berry jack seedlings thanks to Mike T's generosity some years back. To give you an idea, the first started blooming profusely at about 7-8' tall, if I recall correctly. That berry jack seedling has been very vigorous and seems to want to put on a lot of vertical growth (despite pruning to discourage it). The other berry jack is much less vigorous and is probably only about that height (7-8') now & I have not yet noted any blossoming. I've also got a Ziman Pink grafted tree that has probably not held any fruit until about 10' tall. This tree seems to be less vigorous & also seems more amenable to being trained to more spreading growth than the vigorous berry seedling.
So, I am guessing that you could find a clone that could bear fruit in your sunroom but, depending on variety, it might take a lot of work to keep it under control. Some research is probably in order to find the variety that may work best for you. By the way, these trees I mention are in the ground, in HI.
John