Some of the most beautiful LEGO mosaics I have seen are Alyska Bailey Peterson's stained glass windows. This blog would be remiss if we failed to cover her work, so here is a brief summary of some of what she has done.
Here is the Survivors of Trauma window, from the St Silas Church in North Belfast, Ireland:
Here is a stained glass sundial:
She also made a series of five panels based on the days of creation. Here is Day 4, The Sun and the Moon:
Bruce from GodBricks interviewed Alyska about her work, which you can read here. Alyska and Chris Doyle (of reasonablyclever.com) gave a presentation about building with translucent bricks. You can see a pdf copy of the presentation here. Alyska's work can be seen on both flickr and MOCpages. Alyska also runs an art studio, Pointy Kitty Studios, where she sells "fine, artisan-quality accessories and non-traditional photography", including jewelry made from LEGO. What a talented lady!