I've discovered a Web site that offers "fresh mozzarella stretching curd": http://goldenagecheese.com/_wsn/page4.html
Quoting from the site: "Our naturally produced Mozzarella Stretching Curd is produced daily. This is for making your own freshly stretched water mozzarella by hand. This makes the freshest mozzarella... That's because you make it yourself, a great learning experience and great reward at the end!"
It contains no salt, so you can add your own, to your own taste, during the stretching process.
Price is $4.49 - $3.94 lb., depending on how much you order and (here's the good part): "Don't worry about ordering "too much" this cheese can be frozen for up to 6 months, and it still tastes great once stretched!"
Here are illustrated instructions for stretching your own mozzarella: http://goldenagecheese.com/_wsn/page18.html
As can be seen by the photo below, the cheese looks pretty good and, judging from the instruction illustrations, the stretching curd seems to yield a good amount of finished product.
To me, this method definitely seems simpler than the instructions I've seen for creating mozzarella from scratch. I have no idea whether this product will produce as good a mozzarella as the "from scratch" method, but it does look like an interesting alternative to supermarket-bought.
As soon as I have room in my freezer for at least 10 lbs. (which would bring the price down to $4.19/lb., I plan to try some. Has anyone tried it?