More than that, we know the rebels themselves claim to have captured exactly the sort of weapon that would be able to do this (Buk missiles) from a raid on a Ukrainian military base.
http://www.washingtonpost.com/world/europe/malaysia-airlines....
>“The plane was shot down by the Ukrainian side,” said Serhiy Kavtaradze, a member of the rebels’ security council, according to the Russia’s Interfax news agency. “We simply do not have such air defense systems.” He said rebels’ shoulder-launched antiaircraft missiles “have a firing range of only 3,000 to 4,000 meters” and that passenger jets fly at much higher altitudes. ... He denied that the rebels possess the SA-17 Buk air-defense as Kiev alleges."
It could, though, be an honest retreat from a propaganda misrepresentation that has since become more of a burden than a benefit.
(Incidentally, I upvoted the parent because even though the claim may be dubious, noting the fact that the claim has been made is a valuable addition to the conversation, IMO.)
[0] referenced in my earlier post: https://news.ycombinator.com/item?id=8048607
Here's where it was shot down: https://www.google.com/maps/place/Torez,+Donetsk+Oblast,+Ukr...
Here's the territory controlled by the rebels: http://www.nytimes.com/interactive/2014/02/27/world/europe/u...
We know Russia has been supplying the rebels with heavy weapons. It's unlikely that Ukrainian pro-Kiev "neo nazis" marched a heavy SAM launcher through rebel controlled territory. Also, in any case, it doesn't follow that because someone is a "neo nazi" they will shoot down aircraft.