From my research (which was not extensive by any means), it seems like the late Bill Taylor, of Ashton pipes, has created it first. I managed to find an example:

Nowadays, it is definitively the signature shape of Ian Walker from Northern Briars. I admit I like Walker's interpretation of the shape, better. Here are a few examples:

I have always been fascinated by the striking look this shape displays, particularly when Walker enhances it with a silver shank adornment.

But, of all the variations I have seen, the natural finish with the Celtic sterling silver adornment is the one I would go for.

I cannot look at this wonderful pipe and not think that this is, simply, a work of art. If there would be one pipe I would buy without hesitation nor caring about its price, it would be the natural with the Celtic band.