I'm not sure if what I'm after even exists or if it doe's im looking for the wrong thing.
I'm after a framework/application/SDK that allows me to build a desktop application with a HTML/CSS/JavaScript based interface yet still allow for more complex OS interaction with a programming language such as Python (im also familiar with Ruby but as this is a hobby project I don't mind looking into other languages if needed). By complex OS interaction I mean more than simply saving files to the HDD, being able to use pythons libraries would be a big bonus.
The closet thing I can find so far is tideSDK http://www.tidesdk.org but it doesn't seem to offer much past its own API for OS interaction.
Best Answer
Windows 8 (Metro-style) apps would be an option, as you can build your UI in HTML and CSS, and still use Javascript to access all native APIs. You would be limited to the WinRT APIs though. You could also use "real" programming languges in the same project, (C++, C#).
In short, you can build sorta desktop apps for Windows 8 using only the web technologies that you know, without having to dive into a so-called "real" language.