Iraq Body Count, long dismissed by the right as offering inflated mortality numbers for Iraq has serious questions about the Lancet study. And they are good ones.
http://www.iraqbodycount.org/press/pr14.php
Note: They do not dismiss the study as ideologically flawed. They assume an earnest attempt but find the outcome sufficiently flawed (read the details) that they believe there must have been a flaw in the random sampling.