As a final note, when extracting a board which is a sub-items board it would be nice if one of the metrics could be that of the board and item it is connected related to above.
This can be achieved in t-sql, but will break if you change the creation of a sub-item board to start with 'Subitems of '. Creating a self join to the extracted data on:
replace([extract_1].[boards name], 'Subitems of ', ‘’) = [extract_2].[boards name]
and [extract_2].Subitems like ‘%’ + [extract_1].[Items name] + ‘%’
and [extract_1].[boards id] <> [extract_2].[boards id]
Overall, the output you are producing is great- really glad you have the API and it is working really nicely for our requirements. 