mystery nocturnal wild animal in my patch ?

I live in Albury, on the NSW/VIC border. Twice in the past month, I have woken up just before dawn, and spotted this animal. It appears to be feeding on the ground under the trees. It is too big for a cat, dog or possum. It appears to be the size of a Wombat. It barely moves around, or moves very slowly, it mainly appears to me to be in a sitting position, or on very short legs. I have watched it for up to half an hour. I have been tempted to take the torch and have a closer look.
To my surprise this morning, it suddenly took off, very fast, on longer legs ? and now appeared to be about 1 metre in length. I could not tell if it was running, it just moved incredibly fast for around 2-3 metres out of sight.

I am wondering if it could be a black wallaby. I think my first thoughts of a wombat might be blown away, since it moved so fast. I actually have no idea how fast a wombat can move, I thought they were slow creatures.

The common wombat is considered quite rare in this area.

ps, when it took off so fast, it suddenly occurred to me it might have had wings? which contributed to the sudden dramatic increase in size, compared to the grazing position it was in earlier.
I am guessing it is 18" plus in height, and similar width, in the grazing or sitting position. It is dark outside, with just the fragments of a street light showing the dark shadow of the animal.
I am in suburbia, but close to well studied native areas...
see this report page 20....

http://www.lpma.nsw.gov.au/__data/assets/pdf_file/0019/165610/Albury_Regional_Crown_Reserve_Draft_Plan_of_Management_for_Public_Display.PDF
Do any of you have any clues ?