Recently at Infusion (inspiried by my CD Layla Keramat), I was challenged to take a more scalable and dynamic approach to Photoshop. In essence, I wanted to make the Photoshop workflow more conducive to having multiple designers on a single project, with some ability to have easily updatable externalized elements. This was a pretty tall order, as out of the box Photoshop's ability to link to external objects dynamically is simply not supported, save for elements coming from other Adobe products. Internal Smart Objects weren't an option either because those are embedded in the parent PSD which means there is no opportunity to edit them externally. What I ended up creating was a way to have global external components (think navigation bar, button sprite sheets, footer, etc.) fed into one Master PSD file, with the ability to update the elements dynamically, and having multiple designers working on a single project at once, without millions of versioned PSD's floating around. An ambitious undertaking indeed.