Was BillA's WW a Little River (made by Cathar) version or the D-Tek version? All of Cathar's blocks shipped with copper tops as far as I know. As for the tap, they cost over $10 for such a large tap. You'll have a hard time finding one that costs less than that after you include shipping. Also, taps that large require LOTS of force, time, and a very straight path through the metal (hard to do with such a large tap). I doubt many people would want mis-angled barbs. People would probably buy them but not for much, and IMO after the time you put into it, it won't be worth it to sell them. Essentially only a good idea if you have lots of spare time and don't want a 2nd job.
BTW the two upper plates were 3/16" thick IIRC. You could make the top plate thicker, but that would be reeeally hard to make threads in.