If you had to speculate how an unnamed co. implements this type of ad on the backend

[somnamblst]

It is called a Foldover. You can see a demo here:
http://www.pointroll.com/showcase/sample.asp?ad=562

It utilizes two files, the 100x100 banner which on rollover launches the 650x650 panel. The panel remains open until there is a rollout. There are 3 button areas in the panel, one for clickthrough to a website and the other two for navigating forward and back through the pages.

I can and have created the ads but they do not function together unless served by this unnamed company and they do not close on rollout.

I currently have the following on the 100x100 banner:

on (rollOver) {
container.loadMovie("loadUnload.swf");
}

But the entire area of the 650x650 needs to be available to stay open until there is a rollout.