Hey Razak,
You can do pretty much everything you can do on the web in a extension.
Together with our JSApi you create your own extension of the qlikview plattform leveraging our data logic but creating your own front end/client side actions.
With that said yes, you can leverage javascript (which is the language you write your extension in), create dynamic html-rendering with css support.
With html5 capable browsers you play around with the new canvas api, there is some examples in the intergration sub-section that should get you started with some 3D graphs.
