Gosh, we seem to be asking the same questions in different threads of this forum!
What I'm now calling my "yunnanensis" was purchased as itinerans var. gigantea. Below, you state:
"New pups come up directly off the corm, with no long rhizomes (as with itinerans). It forms a dense mat, which itinerans does not."
In my other thread asking the same question, you state:
"Well, there are papers describing both species, both written by Markku Hakkinen. The main difference between Musa itinerans var. itinerans and Musa yunnanensis is the fact that M. itinerans var. itinerans sends pups out up to 6 feet away from the parent pseudostem. Also, M. yunnanensis is very waxy, but M. itinerans var. itinerans is not at all. However, M. itinerans var. chinensis is very similar to M. yunnanensis, exept for the flower and fruit. M. yunnanensis has a very lanceolate-shaped female bud, where M. itinerans has an ovate-shaped bud. "
This describes my plant perfectly, and mine looks just like the picture of yours growing against the wall.
Actually, mine looks like hell right now since I transplanted it about a month ago. It was in full sun and I thought it would appreciate more shade. Oh well, maybe next year.
Trying to get to the bottom of this mess too!