Update!
Thanks for the suggestions, all!
I looked at what was available for order and delivery inflight, but it wasn't quite what I was looking for...they had limited selection, and I think only a 772 available, instead of a 773ER.
Walked down to the Star Ferry terminal in TST and visited the 80m bus model shop there...found both a 1:400 and a 1:200 773ER model! Bought the 1:400 as space is a little tight...but the prices seemed reasonable, and I also got a little Star Ferry model too...!
Sad to leave HK tomorrow, but happy to get back with the family!
Thanks all for your assistance! My kid will be very happy with her models!