I ran into several other references to Matilda Bay. I will just post
some random quotes from them below:

"Oh yeah! I also remember Matilda Bay which you could get in a little
box. We used to get this or the Sun Country 2-liter and fill up our
7-eleven cups. So sneaky.

AP Published: September 8, 1989
LEAD: The Miller Brewing Company said it would stop production of its
Matilda Bay wine cooler in early November because of poor sales.

Matilda Bay Wine Coolers
Remember when wine coolers were all the rage? These were supposedly
Australian wine coolers with bizarre commercials. The characters had
bad accents and did wacky things.

Some coolers, such as Matilda Bay, come in four-packs, a tactic that
not only makes them look more like a soda, but also ensures that people
will buy the product in quantity.

Matilda bay wine cooler mirror with palm trees. The mirror measures
approximately 16 inches wide by 19 inches high, with a plastic frame.

Through college, my beverage of choice was wine coolers - Bartles and
Jaymes (which now I believe is utterly undrinkable) and the favorite
Matilda Bay (Australian accent: "Comes in a box, so it's easy to pour!"
- I also have a neon signn with lovely rasta colors).

Well, the unopened case (of four one-gallon boxes) of Matilda Bay wine
cooler I bought back in 1989 are still good. Does anybody remember OK
Soda or Matilda Bay? Fond memories?

do you remember a wine cooler called Matilda Bay? you could buy it in
bottles or in a little package that had a spout. they quit making it in
the late 80's. it didn't taste like alcohol at all, and the girls would
get pretty farked up on it pretty damn quick. if any of you guys
remember this stuff, and miss the taste of a "matilda kiss", then try
this stuff. it's stronger than matilda bay, but it tastes exactly like
it.

You are bidding on a Matilda Bay wine cooler plastic lined bottle cap,
from Miller Brewing Co, Milwaukee, Wisconsin. This one is the rarest
variation of Matilda Bay.

matilda bay wine coolers, noncarbonated so you can chug 'em faster
unfortunately they've been out of business since the early 90s, so i
make do with strawberry-kiwi-everclear daquiris."