Hi to all!
We have experiment with including one panorama (or whole tour) inside the other and get the interesting result. You can create the corridor with the different panoramas without any restrictions. May be only the screen dimension. What is strange, that the all panoramas are good working. You can rotate and call the actions in any of them. But if you want to include the pano into itself, there are only three levels of the including. The 4-th pano stop loading.
The example you can see here: http://www.classic-ru.org/3/
To be interesting you can see here the different variants: one pano into another, the object in the pano, the pano into itself and the corridor with different panos. You can try the different combinations of this variants.

Hello, Martin!
we use this plugin http://www.krpano.com/plugins/userplugins/htmlpage/#top
You only enter the html pass to your object

Hello, Martin!
This plugin can include any html you need. On the site you can see only the most common examples (Fliiping book , photo galery, Object, etc ). But the usage restricts only by your fantasy. Here you can see the examples with the games inside your pano http://www.classic-ru.org/3/test2.htm
You don't need any extra plugins.
Of course, if you want to add the data base to your pano, you need to know php,sql and many other things. But if you need to place the ready product, you must only write the path to it. And don't include the whole sites on mobile or youtube video anywhere.

Hi,Toni!
Very interesting idea. It's really the other way.
Please, can you show the really example of pano inside pano. Not the hotspots with pano in empty world. Because the main problem is the coordination of the background pano and the upper one in HTML. You can easy create such kinds of worlds in the 3D editors, like 3dmax or mayea, but there are the problems with the publication without large viewers.
If you can't, then it's not the solution. But only the start point of the working process.
If you can, well it's really expands the arsenal of panoraming photography and we all are interesting in it.

Hi, Ramiro!
You write the back form on PHP and put it on your server. For example, in the same directory that your tour. You need your server to support PHP. Usually it is so.
After it you will get the filled form on your post address (or what you order.).
We have the PHP form in our download (and in examples). You can create your own on it's base. Or write your own. Or find somewhere ready for use PHP form.