Not in Index Kewensis nor the APNI database.

At http://elvis.cqu.edu.au/cqulibrary/cqucol/thozet.pdf there is a reproduction of the pamphlet "Notes on some of the Roots, Tubers, Bulbs, and Fruits used as vegetable food by the Aboriginals of Northern Queensland, Australia" by A. Thozet published in Rockhampton, Queensland in 1866 to raise funds for the Rockhampton Museum Building Fund.  The pamphleteer acknowledged his debt to the works of his "indefatigable friend, Dr. Ferdinand Mueller, to whom the scientific and commercial world owe so many valuable discoveries."   There was obviously an intention to publish a set of illustrations of the plants "at a future period" but this seems not to have happened; we might otherwise have some clue as to the identity of Musa brownii.   Musa brownii is listed as number 33 of a series of plants that can be eaten without any preparation, although Thozet seems in some doubt as to whether it actually needs cooking first.  The note is as follows:

33. Musa Brownii, 1?. Muell. Native Banana. Morgogaba, Cleveland Bay Tribe.

Champion notes that the name is cited in a paper by Pucci (Boll. Soc. Tosc. Ort., 296, 1906) but lacking a description.