I snapped these pics of a mutation Cuban around 7 years ago. The breeder was working towards establishing them at the time. From memory they were being referred to as Australian yellow Cubans. I know a small number of breeders acquired birds from this Sydney based breeder and recall seeing them offered for sale at a couple of bird sales back in 2014. I have no idea of the current status of this mutation, but would be interested to find out if anyone in the finch community does know?

There’s a guy John breeding quite a few down at Cobargo
That’s great. How did he go with the fires?
Apparently they got got very close the wind changed direction and saved him
Thank goodness for that!
MIght be the same person: https://webcache.googleusercontent.com/search?q=cache:pbUjcr_RcC0J:https://www.petlink.com.au/Classifieds/sale/2743179.html+&cd=1&hl=en&ct=clnk&gl=au