You know, there is another interesting technique that can be done to mimic the appearance of stained glass, and that is to use a black fabric background.
Then, cut the pieces of the pattern and arrange them on the black background leaving a small space between the pieces that the black background fabric shows. That gives the effect of the bias tape or "leading" in the stained glass window.
But, it only really works well wtih simple patterns. Complicated patterns with lots of lines don't work so well that way. You have to use the bias tape.