I'm not sure how the USDA zones work, as the Norwegian system is different. Any links about how it work...?
Erlend:
Jeg er i H2-3, det er vel du også? Jeg vet ikke hva gjennomsnittstemperaturen er her, men sist vinter var det laveste -16°C, men det var et varmt år, vanligvis vil det være nedi -20°C. Hva er de laveste temperaturerene der du bor?
Translated: I'm in (Norwegian zone) H2-3, I guess you are that too? I don't know what the average temperature is here, but last winter the coldest temperature was 3°F, but it was a warm year, usually it would been down at -4°F. What are the lowest temperatures you'll get where you live?
I know Musa velutina is pretty cold hardy, as are (as if you didn't know) Basjoo.
Ensete is an own family inside the Musaceae family, so it's called Ensete ventricosum. But I don't know how hardy it is. From what I have read, it is at least a little hardy. But Ensete glaucum is more hardy than Ensete ventricosum, isn't it?
I have only read about these, I haven't any experience yet. The others I haven't read about, so I don't know.
Gard