The nomenclature of this plant and its close relatives seems particularly confusing.  There are obviously three very closely related forms of Musa acuminata but sufficiently different for Norman Simmonds to treat them as distinct subspecies:

Musa acuminata subsp. malaccensis (H. N. Ridley) N. W. Simmonds
Musa acuminata subsp. sumatrana (O. Beccari) N. W. Simmonds
Musa acuminata subsp. zebrina (H. N. Ridley) N. W. Simmonds

A number of horticultural 'forms' at least of the last two subspecies seem to be in cultivation.  These tend to be given different names by different nurseries or different literature e.g. 'Sumatrana', 'Zebrina', 'Rubra' and 'Rojo'.  The names are used sometimes as if they were species names.  This is wrong.   The names are used sometimes as if they were cultivar names.  This is also probably wrong in a formal sense because most are probably referable directly to the subspecies.  However, some plants may indeed be distinct selections worthy of cultivar status.  Unless and until someone collects all the cultivated 'forms' together in one place and evaluates them side-by-side it is likely not to be possible to determine their true individual status.