OK, my first amp has been usable for over a year.  It's provided plenty of aural joy and thermionic warmth to my chilly basement, however, I hadn't actually glued or oiled the wood frame, added feet or covered the power tranny.  Finally, I made time.  To add a mounting surface for a set of Vibrapod feet, I decided to add corners to the frame.  To add strength, I dowel jointed one side of each triangular corner.

The corners are inset about 3mm to allow a perforated aluminum panel to sit inside the frame.  Drill a hole in each triangle, ream a corresponding hole in each corner of the perforated panel, screw it all together and voila: