@Rich, so far the v6 stacks are still in their infancy. They'll get smaller as soon as we figure out the bare minimum for comms and offload most of the bookkeeping to a gateway. That's what 6LoWPAN does.
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.