I read that they are considering the possibility of a very small nuclear device that went off, one just enough to take out a plane and remove most of the traces of it.
That's just so wacky.
But for giggles let's for a minute assume a terrorist organisation actually had a small scale nuclear device of such a description:
1) it would be infinitely easier to just detonate it in public place instead of trying to smuggle it though screening and rigging it to explode at altitude (or time in flight).
2) it would be far more beneficial politically and "terror-like" to use it in a populated city or some such.
3) they would be bragging from here to Timbuktu
The human mind is great at finding patterns were none exist, or the links are so ridiculously tenable, so best to occam's razor.
Most likely: The plane had a mechanical issue that caused it to break up in the air.
A small possibility: A pilot went rouge
Buckley's chance: A terrorist bomb of some sort
Sweet FA: A nuclear device