Saddle tees for irrigation?

I'm wondering if there's a saddle tee made for adding on to existing underground pipe without digging up enough to slip in a standard T. I thought I could just slice a standard tee in half, glop some cement on it and secure it to the pipe with spiral clamps, but the $!&#@ that designed the standard tee made the middle 2" or so slightly smaller in ID than the rest of it, so it won't mate to the pipe. I once saw such a thing adverised on the Web, but they only sold them in large quantities -- I've never seen them sold in, say, packs of 10. I could use 1x1, 1x3/4, and 3/4x1/2 if anybody knows of a source.

Glue on saddle tees are available. The port is somewhat small, so I would not recommend it for a branch supporting more than 1 or 2 heads.

Another suggestion is to use a slip extension coupling. This necessitates a little more digging but can be inserted in the line without needing to move the exisiting pipes longitudinally.

The slip coupling is the way to go.