Double NAT'ed as in you had two devices routing your network? In other words, CL 660 routing to a say a Linksys wireless router and so forth?
Correct. The 660 was routing and my Linksys was routing. This was causing addressing issues.
Update: Yesterday (saturday) afternoon into the evening there were some problems streaming hbogo. Once again, only a portion of my bandwidth was seen and the middle of watching a movie already in session -- we were interrupted, twice. Debug mode showed 0.5Mbps of 0.8Mbps. Shifting to Netflix and then Hulu+, these played fine. The issue cleared up an hour later.
I am convinced that the combination of of DSL @ 10Mbps or lower and the current HBOgo stream from my location in Florida will have intermittent issues. There are several forum posts discussing HBOGO's streaming protocols as opposed to Netflix's or Hulu's and I believe this to be correct as well. I do not have any other options at my location for better connectivity. Although CL service goes up to 40Mbps, this is not available to me.
So ultimately, simply based on my tests it is a bandwidth/connectivity issue. None of my friends using cable are experiencing any issues whatsoever.
If anything else comes up I will post it here.