I'm actually slowly spending a bit of time on the side chewing on how to write a simple user land network stack (mostly because I want to really understand standard transport protocol semantics and performance), so looking at the low power / embedded regime and trying to understand that piece too is just kinda fun :)
Nice starting point to get a feeling for power/throughput trade-offs in low-power wireless networking: http://sing.stanford.edu/pubs/sing-08-00.pdf
Sensys 2008 paper about web services for tiny IoT systems: http://research.microsoft.com/en-us/um/people/zhao/pubs/tws0...
Proceedings of the IEEE 2010 article on IPv6 for low-power wireless: http://www.cs.berkeley.edu/~jwhui/pubs/jhui-ieeeproc112010.p...
Sensys 2011 papers on trade-offs and interoperability of RPL mesh routing for low-power IPv6 and on TCP for low-power wireless: http://dunkels.com/adam/ko11beyond.pdf http://dunkels.com/adam/duquennoy11lossy.pdf
There are also two books on the subject and a bunch of relevant papers on the Contiki website: http://6lowpan.net/the-book/ http://www.thenextinternet.org/ http://www.contiki-os.org/support.html
(Full disclosure: I'm a co-author on a bunch of those last pointers.)