Yes it is technically possible that a BUK system shot down the plane.
@Ryathal- In contrast to your article, I'd like to post THIS article. My point is that there are many working theories as to who shot the plane down, and what type of weapon(s) was/were used.
I found this gentleman's clip does a good job of putting western media coverage of Ukraine into perspective with rather solid facts to back everything up. That's not to say Russia does not spin propaganda, but it makes you wonder about how trustworthy western claims and coverage is.
Until a thorough INTERNATIONAL report, provides proper analysis proving guilt, I suggest presuming all parties INNOCENT UNTIL PROVEN GUILTY.
There was also a clip of a BUK system, minus one missile, driving on Ukrainian-held territory that day. Unless the "rebels" managed to sneak it past the Ukrainian army, (which would point to their utter incompetence, improving the chance that it was Ukraine that shot the plane down by accident),I don't see how this could be possible. Putin's plane was also supposed to have been in the area at the time, Ukrainian hot heads may have thought they were shooting down the president of RU.