The original inspiration came from a web application which had the looks of a windows forms application - the same form surface, buttons, etc, and of course even the menus to a degree. It was being used at my client's end. It is a very old application; probably dated back to the time where DHTML was hip. The problem with it obviously was: it contained very obsolete markup. Those sort of markups only work on old versions of IE (< 5.0). And moreover, the damn thing wouldn't render on any other browser.
But I really liked the effort put into the development of the various web pages. It was developed by a different vendor; we had to maintain the application - as usual we had no idea who that vendor was, and what that vendor had done.
I am not going to really explain everything in detail. The code is simple, and the design is pretty straight forward. I am just embedding the example here: