That's weird... I used a flash-based article reader several years ago (almost certainly prior to January 2009) which had a page-turning animation. I think it was used either for a product catalogue, or possibly even for an electronic magazine published by Aviation Week (DTI Weekly or something like that). You clicked on the edge of the page with the mouse, and dragged it across to turn the page. I thought at the time that it was pretty, but an otherwise useless gimmick.
Going from using the mouse on a PC to using a finger on a device where the mouse is replaced by a touch screen & finger is almost the definition of obviousness...