I’m trying to figure out how to build a layout like this using HTML(5) and Twitter Bootstrap:

It does not need to be supported in IE < 9 (Although 8 would be nice) or older versions of Firefox/Chrome. It should however render nicely on mobile devices although we are aware that the fixed left menu is a problem on very small displays. Its primary use is on desktops and tablets.
I have been trying to modify examples/similarities like these this, this and this but without luck.
Do you know of any examples where I can find a layout like this or do you know how to make one? Any help would be much appreciated!
This may work:
HTML
CSS
http://jsfiddle.net/rGBAt/1/
At the moment it has the overflow-y set to scroll but you may want to add his using jquery so it doesn’t always add the scrollbars in browsers like chrome and I’m not sure if it’s compatible with the Twitter bootstrap
this version adds the overflow when the content gets too big:
http://jsfiddle.net/rGBAt/7/