Moving Pictures "The Constitutional Convention"  (3:23); Simon Starr A Typical Delegate

Snapshot of the Convention in Philadelphia
12 states represent (Rhode Island refuses invite)
Total number of delegates 74 sent to attend

Representing the old revolutionary generation

Only 3 had attended the Stamp Act Congress (1765)
Only 8 had signed the Declaration of Independence (1776)
Only a little more that ½ had served in the Continental Congress (1774-81)

Representing the people who the revolution cast up in the position of power in America 

22 had served in the Continental Army, 3 under GW
55 of the delegates came from the top 5% of the American wealth pyramid (not the artisans and working men that framed state constitutions).

Many of the men were unknown to the old revolutionaries and unknown to state politics. They were men ready to think continentally

HISTORY TALKS: James Madison, Father of the Constitution (7 minutes)

Charles Beard, An Economic Interpretation of the Constitution, 1913

A majority of the members [of the Constitutional convention] were lawyers by profession. 

Most of the members came from towns, on or near the coast... 

Not one member represented in his immediate and personal economic interests the small farming or mechanic [artisan] classes.

The overwhelming majority of the members [of the Constitutional convention], at least five-sixths, were immediately, directly, and personally interested in the outcome of their labors at Philadelphia, and were to a greater or lesser extent economic beneficiaries from the adoption of the Constitution. 

[Of the 74 delegates:] 
 40 were holders of public securities (holders of Continental and state debt) 
 24 were creditors (lenders of money) 
 15 were southern slaveholders 
 14 were involved in land speculation 
 11 were involved in manufacturing, commerce, and shipping

Dr Bill O'Brien 28 May 2013 YouTube Lecture on Charles Beard