It's still not entirely clear to me whether OpenTag (HayTag, what's the difference?) on an 8bit AVR (not arduino).
I have no other relationship with panstamp except being a "happy user", but I think it deserves a bigger community. Take a look. The SWAP stack is great, even if its all-HEX approach isn't the most user-readable one... If you can make a side-by-side comparison with DASH7, I'm interested.
Looks like an incredibly complex protocol that's gonna take some serious processingpower, so it's not quite clear whether it'll actually be "low-power" to do all thatstuff. It took Maxstream/Digi 2 or 3 years to get the zigbee mesh protocol right.
RF transmit has been stuck at 0dBm/15mA for a decade.
Dash7 all sounds good. Not sure it will take over the world, however, :-).