There are a few AppleScriptObjC tutorials and examples at sites such as
MacScripter and
Mac OS X Automation, but most out there is in Objective-C. The image you posted is pretty much custom built, although a lot of the pieces are available in Xcode's Interface Builder. Pashua just has what is available in its documentation, and I would suspect that it was built using Xcode.
There are quite a few out there that don't like to use the Interface Builder at all and build everything from scratch, so I suppose it depends on exactly what you are looking for. Finding your way in the wilderness known as Cocoa is usually what takes time, no matter what language you use.