I've been thinking about doing this for maybe a year now but only started in the last 2-4 months. Started with a Japanese-made Orlando classical I got in a pile of junked guitars, most of which had been strung once with steel (despite classical design and construction). The bridge was missing, having been glued back on at one point and ripped off again by the steel string tension.
I started by plugging up the tuner slots and other holes in the head and hiding the main plugs under a (thick) veneer of cherry. Then had to route out the back of the thick head so the new tuners could stick through enough to get strings on. Added a bass guitar tailpiece and made a bridge of more cherry (after making a router base with fence for the Dremel). Nut and saddle are bone blanks I found on ebay.
Instead of linking individual pictures, I'll just link to their set page on flikr.