On July 24, 1787 a committee of five (John Rutledge (SC), Edmund Randolph (VA), Nathaniel Gorham (MA), Oliver Ellsworth (CT), and James Wilson (PA)) was elected to draft a detailed constitution. The Convention adjourned from July 26 to August 6 to await the report of this "Committee of Detail". Overall, the report of the committee conformed to the resolutions adopted by the Convention, adding some elements. (Wikipedia)

Tom Jefferson was Minister to France from 1785 to 1789 -- he wasn't even in the country for the Constitutional Convention; he did write the Declaration of Independence and other important documents, however. Note too that three of the five member of the "Committee of Detail" were from northern states -- I won't say non-slavery states as slavery existed at that time even in the North.