I think some bowlers absolutely bowl beamers deliberately.
Let's be rational about this, international bowlers are the very best in their fields. I personally find it very difficult to believe that any top-class seamer could miss his length by the 20-odd yards needed to turn an ordinary ball into a beamer unless, perhaps, he's attempting a complicated slower ball.
Sreesanth's beamer to Pietersen at Trent Bridge was an absolute disgrace, not only was it head-height it swung considerably in flight and KP did well to avoid it. The irony is that he was actually fined half his match fee for a (relatively) harmless barge on Vaughan; the beamer passed without censure, presumably because intent is so hard to prove.
I don't want to single Sreesanth out particularly, but his beamer was the first one I thought of when I saw the thread title. Brett Lee also has a bit of "previous" in this respect; I remember him beaming Abdul Razzaq, which was a heck of a coincidence as Razzaq had sent a headhunter down to Lee earlier in the game.
We live in litigious times so I'm accusing no-one of malice, but I do think it'd be naive in the extreme to think no bowler had ever deliberately beamed someone.