Nicely done!  What kind of displays are they, common
anode or common
 cathode?  If you send me the part number or datasheet, I might have
 replacements here. (I have LOTS of displays)  I can put them in your box. 
    The ones installed are TIL312...
   Nice!  I have a Mendel but have not yet gotten it
working. 
    what is missing? ;o)
    BTW, completed board:
http://www.tabalabs.com.br/outros_micros/sdk86/20.jpg