If you search for a well known person, e.g. "Barack Obama" in Google on an iPhone (and maybe other devices) you can click a button which brings another page over the top of the main page (or change your user agent to an iPhone on a desktop). This is the kind of thing I need.
I also need to be able to keep clicking pages (so if each page opened had further links) opening up more page as needed on top.
I want to be able to specify (a) a section on the main page (which is hidden until click a button and the content slides over) and (b) a URL on the same domain which slides over once a button is clicked.
I have seen Scott Robbin's PageSlide and I don't think it does all this, so I'm looking for an alternative.
I'm not looking for something like Fancybox, it must be a page slide over the top thing.
Ideally the additional content could also be loaded asynchronously in the background.
I am happy to pay for this, so if it's not free that's fine.