More anecdotal evidence of plenty of XB1s in stock, probably the largest piles I've seen.
http://www.neogaf.com/forum/showthread.php?p=96411272#post96411272
http://www.neogaf.com/forum/showpost.php?p=96446564&postcount=2516
Dat Cboat massive yield issues
For shits n giggles I compared Phil's b4stats site (http://temp.conceptics.ch/bf4stats/) to get an idea of rolling average of BF4 players and compare that to actual recorded sales as of end of Dec (which was 4.2m PS4 and 3m One). The ratio is in fact pretty close.
One ratio to PS4 sales= 3/4.2= 71.4%
BFstats avg online players for the lifetime of Phil's site (about two weeks) ratio of One players to PS4=34/45.7=74.3%
Most recent day= 26.4/33.2=79.5%
Last week=33/44.4=74.3%
Seems at least the ratio of online PS4/XOne BF4 players on avg (because it will vary greatly based on time of day) is decently close to recorded hardware sales...perhaps this could be a defacto sales tracker.
If Phil keeps the site up over time we can get more data, and see for example if it corresponds at all to monthly sales trends etc. This might be difficult though, since it's worldwide stats and NPD's are USA only. Still, I'm guessing the ratios may be fairly constant.