DIY Large Mirror Frame using a mirrored closet door. Incorporate a piece of paintable textured wallcovering to the inset panel above the mirror. Add decorative trim or molding for an extra design motif.
using a cheap mirror from Walmart or Target: Attach to a piece of plywood (paint it first), then add either crown molding or any other type of wooden accents. Although I've never seen cheap mirrors that wide at walmart.