This is my estimation:

Boss: Sal DeLaurentis
Cicero: James Inendino or Sal Cataudella
Elmwood Park: Marco D'Amico
Grand Ave: Albert Vena
South Side: Frank "Toots" Caruso (His pop, Frank "Skids" Caruso ran a gambling crew for years on the South Side)

Around 30 guys is probably a decent estimate. The DiFronzos are pretty much retired, ditto Andriacchi.

Some other info:

Pizzaboy is a NYC guy; he has no interest in debating Chicago.

Ivy League isn't much into guessing, but he is an encyclopedia of LCN cases both past and present, so if you have questions concerning a particular case, he is your man.