@Rich, the numbers I've heard so far are that you can't even consider v6 in less than 64MBs of RAM. On the SoCs with M3/M4 they're coming with 256M. So, it's not much of an issue as long as the application is frugal.
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. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.