On the B&H site I see that the PMW-320 is 'no longer available'. Does this mean that the camera is discontinued by Sony?

Could be true. The kit version with a lens looks to sill be available though.

I had a 320 on order from B&H for the entire month of July. Beginning of August, they sent me an email that said it wouldn't be available until the end of August. I called several other dealers around the US and was told that new 320s would be hard to get because Sony was allocating them very selectively. One dealer said she might be able to get me one in a few days, but the Sony rep wanted to know what kind of projects I was shooting and for who. After telling the dealer I had 10,000 reasons and it was none of the rep's business who I was shooting for, she informed me that it would the end of August before I could get a camera. I finally found a dealer with access to some B-stock cameras. I bought one and it arrived last week.

Strange business. It indeed appears as if the 320K (with kit lens) is still sold, but Sony has stopped delivering the 320L (without lens). I bought mine without lens a year ago and I use it with a prime Canon HD wide-angle lens. Perfect combination. Seems strange they would abandon the offer without lens.

Probably a production run issue - make a container load and the popular one sells out. Maybe they assumed few people would want a lensless one - so made less, but then they went quickly. They won't discontinue selling until existing stock has run out. A clue that the end of the model is nigh, maybe?