I've waited to see if someone would have an answer for you, but apparently not. So I'll give you my completely uninformed thoughts.
My first thought was Broder's, but I see you've been there. I'd give a call to Buon Giorno in Lilydale and see if they might be helpful. Or Cosetta's - although I don't recall seeing any package goods there that weren't at Broder's or Buon Giorno.
I did a quick Google search and it looks like packaged squid ink is a Spanish product. I don't have a particular lead on this, but perhaps others might.
My last two thoughts are totally random - but between the two of them, they sure carry a lot of esoteric goods: Bill's Imported Foods at Lyn-Lake or United Noodle. It appears that squid ink may be used in some Japanese cooking, so UN may be helpful. Bill's has a lot of pan-European goods.
So - these are just my random thoughts that may be helpful. (Or not!)