I routinely buy cans at the shop down the street from me in Thang Long International Village. It's just a little supermarket in the apartment complex. I'll try to get a photo of it later and post it as a new spot for you.

They sell it in cans, singly and by the case, at Big C. Cans are about 10.5k VND and multiply it out for the case. For reference, it is a little under 2x the cost of Bia Hanoi in cans at the same market.

I've also seen it at citimart in vincom towers - both gold and black (in cans)

Yup, Citimart's got it for sure.

I've entered the supermarket closest to me that has it. You can check it out here:

www.newhanoian.com/details/venueid/999