Looks good ! You have a good sense for where to put in lots of details, and where to live things sort of plain.
I've been meaning to post some ideas I had here, but if you will spend a bit of time with google there are some great sites out there on clay pipemaking and the use of molds and presses in the old days. Heather at
http://www.dawnmist.demon.co.uk/ probably knows more about clays than just about anyone, that site is full of info and from what I hear Heather loves talking about clays and answering questions.
I dont think you plan to do things the old fashioned way, but it might be easy enough to make a mold thats just for your stems, so you end up with a perfect stem, a perfect airway and a perfect mouthpiece every time.
My thoughts were (if you plan on doing enough of them) just using a large wooden dowel, drilling out the right shape inside it and then splitting it down the middle. or cutting it in half first and then using a dremel to shape the right size cavity for molding stems.
When its done, you could fill it with a roll of clay, clamp the two halves together in a vise to squeeze the clay into shape, and then drill your airway by pushing a straightened out clotheshanger through the mold.
Then its just a matter of attaching the perfectly formed stem to the bowl with slip, or however.
I dont know, just a thought.
If you really sucked at this, I wouldnt reccomend going to all this hassle, but the pipes are actually pretty neat. If the "pipe" aspect of it can be done as well as the "art" aspect of it, I think you have something there.