I made this simple mirror for out powder room a few years ago out of some scrap cherry left over from Dr. SWMBO's desk. This is a simple through mortise & tenon design and uses a "stock" mirror from the 'borg. The pegs are square and pounded home. They are not necessary for strength so you could easily just inlay some pseudo-pegs if you choose.
The JPG is a little small, but the dimensions are visible. The WMF file appears to be larger and easier to read if you are on the Windows platform. The DXF file can be imported into any CAD package that supports Autocad DXF import.
http://sawsndust.com/downloads/shaker-mirror.jpg
http://sawsndust.com/downloads/shaker-mirror.wmf