Download my entry for the Scripted Competition... There is a sitting Barney in it. But it wasn't my Idea.. The tutorial on the original sitting Barney from HL was posted years ago on 'the spawning tank' and some of the dimensions are not quite right. It works but needs work.
As for the Bomb, why don't you build a small test map and see if it works... if it does you can let us know.