> While there are a number of great CARDIAC simulators out there (see Building a CPU simulator in Python for instance) and even an FPGA implementation (Al Williams - Paper to FPGA) there is nothing like holding and operating a physical device.

"Paper to FPGA" sounds like a cool idea, though the point of CARDIAC seems to be that you perform the operations yourself (by carefully following its flowchart/control specification and manipulating the cardboard device.)