EmphemeraNow.com
This is the source of all the great automobile illustrations on this site

LCCI - SACK Colorado   (Sunday Afternoon Car Klub) - This is the LCCI region located at Denver Colorado. 

Great Autos Of Yesteryear   This is a very large and very established Southern California based group.  They host an annual meet each JULY in San Luis Obispo.  There is a section called the garage which requires a password.  They have provisions, via email to obtain this password.