Theres one in use at a cafe bar located in Sydney Airport T2 (Virgin/Deathstar terminal). Cant remember the name of the place but it usually has a queue. Not hard since it is opposite such great coffee establishments like Crappy Kreme donuts.
I think its a good idea. It was in constant use and IIRC had two hoppers. In fact my doppio cap was one of the best Id had from a takeaway establishment in a long time.