Regarding your spaghetti question: Spaghetti is meant to allow you to create custom shows using existing .ild files (you already know where to find those). Spaghetti takes a multi-layered approach to show construction. Lets say, for example, you want to make a frame that contains a circle with a line across it. You have two .ild files, one with a line and one with a circle. If you place the circle on one layer and the line on another layer, the output will be a circle with a line through it. Using this method you can combine .ild files to get frames containing multiple aspects.
As far as creating your own .ild files from graphics you have around, there is other software that you can use for this. I believe that if you download the demo of Mamba Black that it comes with a full version of Mamba's frame-creation software. When you install the demo, it installs the frame creation software on the side. I haven't tried this personally, but I was told it works.