I think there is a (probably small niche but maybe growing) market for something that allows users to create digital signals with various levels of control from the bit level to the Byte level to relatively long strings. Something that allows control over speed/frequency, voltage, pulse width, rise and fall times, plus much more in the way of protocol management. The Total Phase Aardvark is a step in the direction - but with more functionality and for multiple protocols. Kind of like a cross between an arbitrary wave form generator and a protocol emulator. As it evolved it would have a continuum of capabilities ranging from highly custom bit banging to libraries. The use cases would range from teaching to simulation support to debugging. The standard protocols would range from RS-232 to I2C to SPI and CAN and maybe others. It would allow everything from waveform shaping and sequencing to error detection and correction manipulation. It could be both data entry driven and graphically manipulated. It would allow users to have one, two, or more nodes (boards) in combinations of point to point and master/slave/multipoint networks. All of this wouldn't happen on Day 1 but it be designed as a modular and very extensible platform. Maybe something that leverages other platforms from Arduino to TI Launchpad to take your pick - it would have/support software and hardware components. Probably would have some libraries or utilities to leverage oscilloscopes, logic analyzers, and maybe arbitrary waveform generators. Kind of a big wish list but the more insight/visibility and control it lends to observing and manipulating communications the better. The Swiss army knife of digital communications for learning, developing, and testing - but designed to leverage other resources so as to be relatively low cost and/or open source. Something that helps take the nearly invisible and mysterious and make it more visible, understandable, and managable.