Illia

There's a rather rare variety called Chundillakkunnan that is said to ripen in 3 months, possibly less. Gran Nain is said to ripen also in under 4 months, same with Rose and Goldfinger. This isn't guaranteed with everyone though, and conditions are the big variable. Others that ripen fairly short are Rajapuri and Pisang Jari Buaya. There's others out there too, even short seeded ones like Velutina, which though seeded with little production, will give ripe fruit from a baby plant in 9 months. (ripening time about 2 months)

Rose is cold hardy, don't know how cold. Pisang Jari Buaya seems to be confused with Monkey Fingers from time to time and is said to be cold tolerant but is too rare to really be confirmed, though Monkey Fingers to some is considered one of the hardiest, so, who knows. Gran Nain isn't too tolerant though. Rajapuri is very cold hardy. Not a clue on Chundillakkunnan's hardiness, as it was pretty much publicized as a fast ripener under 2 years ago.

I've no full experience on these varieties yet, this is all on my research. Some of this research is based on tropical growing conditions, so others' may be longer due to stress in bananas from cool, dormant, or cold situations.