As I've noted, software defined peripherals has been done before, by at least Scenix/Ubicomm (bankrupt), Parallax Propellar, and the XMOS chips. If you wanted to stretch a bit, you could include TI's PRU (featured in the BeagleBone) and the Cyprus PSoC's (programmable analog peripherals).
Another comment: parallel programming is still hard, whether it's cooperating virtual Arduinos or cooperating PLC tasks (side story: I recently realized we had some deadlocks in some structured text PLC code involving a couple of separate cooperating programs. It escaped dedication because it doesn't show up under normal circumstances...)
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Are the design challenges the same as with embedded systems, but with a little developer- and IT-skills added in? What do engineers need to know? Rick Merritt talks with two experts about the tools and best options for designing IoT devices in 2016. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.