I read the discussions on this forum and followed the links the provided. There were two threads, if I remember correctly, and I think there must have been at least two links.
The reason I remember is because the price was different each time. First link said (from memory) about $25 million per plane, and the next time it was much more than $40 million per plane.
It stuck in my head, because I couldn't imagine why there would be two different prices and because I know much Frontier is paying for the A318.
I had noticed that it doesn't show up in the Airbus website, which also surprised me, but it isn't unusual.
I haven't checked this morning, but as of yesterday the Airbus site didn't mention the sale to the Qantas low fare carrier, JetStar, which is pretty big deal for Airbus - not in sales, but in getting the whole order.
I don't know anything about the practise of "hiding" a signed deal. I'm not sure why they would, but then I don't make airplanes.