While your question is about PAC Display objects, it seems a good opportunity to mention Opto's often overlooked collection of Visio graphics. The collection has illustrations of current and older Opto controllers, brains, and I/O modules plus other equipment like terminals, network switches, PCs, and other hardware. You can copy these graphics in Visio and paste them into PAC Display as rescalable vector-based objects, so you don't get the "jaggies" like when you resize a bitmap image (JPG, etc.).
More info: http://www.opto22.com/lp/visio_libraries.aspx