I saw this new technique (at least new for me) in the November Stampin' Success:
To create the stained glass look you take a piece of vellum cardstock to the size you need. Take the stamped image you want to use (use a line art stamp - something you can color in) and stamp it on the vellum, use StazOn or Craft inks. Next, flip the vellum over and fill in the image with color using Watercolor Wonder Crayons. Strong, vibrant colors are the best since they are more visible on the reverse side. Use an Aqua Painter or Blender Pen to blend the colors of the image. Then just mount the vellum (colored side down) on to a piece of Whisper White card stock using Mini Glue Dots. Then, adere the image and background to your project using Stampin' Dimensionals.
Sounds Simple! I am looking forward to trying it! I think I'll try it tomorrow! Hopefully, I'll find the time!