Well there was . . once upon a time .. We had a super chap called Satish. He made just such a plugin -WinMorph. I almost but ultimately couldn't make it work - no change there then! But I doubt whether it is/has been updated for Vegas7?
Maybe others can give us a better update.
Anyways, great link, thanks - beautifully achieved morphing.
You can't beat the price on Satish's morph program, but if you want better functionality, I would recommend Abrosoft's FantaMorph.
You can't really do morphing as a plug-in because, as you will discover when you use any morph program, they work by matching up specific points in each still photo. For instance, you usually outline similar locations around the eyes, ears, and nose of each face you are going to morph. The better programs let you automate this process, which is a HUGE timesaver if you are going to do more than one of these.
In addition, the better programs will also let you morph video a technique pioneered in an old Michael Jackson video (I think it was "Black or White").
Ah, yes it was "Black or White" and here it is. The effects begin at the 5:30 mark. This video was done a LONG time ago, and is still visually stunning. Jacko may have been (and still is) a wacko, but he sure attracted top-notch production talent.
[Edit] Odd, I just noticed that, in my browser, the counter on the YouTube video counts down and not up. Therefore, if your counter goes down, the mark for the start of the morphs is 0:58.