Could you dismantle the bookshelf for parts and use it to make shelves inside your wardrobe to put your books and papers on?

I think for the desk part I'd either be creating a fold-out desk with hinges and fold-away legs, or just installing a heavy duty shelf with a slide-out keyboard tray. if you work from a laptop you could make the slide-out tray big enough to hold a closed laptop. That way you have the shelf to hold printers/screens/etc. A hole cut into the back of the wardrobe would allow power/telephone/network cables or anything else needed.

I think the slide-out or fold out shelf is important ergonomically as it will allow you to slide your chair in to a comfortable position when working, and you then still have all the space in the bottom section of the wardrobe to be able to add storage - more shelves or filing cabinet-type storage.

Good luck with it! Would LOVE to see your project when it's done =)