I don't believe an answer has been forthcoming on this (maybe I missed it) but the North Suburban in addition to Warren was:
Libertyville
Barrington
Dundee
Woodstock
Crystal Lake
Palatine
Maybe? I know I'm close anyway.
North Suburban
Formed in 1948, its charter members were Crystal Lake, Grayslake, Lake Forest, Libertyville, Gurnee Warren, Woodstock and Zion-Benton. In 1952, Grayslake left and was replaced by Barrington. McHenry joined in 1953. In 1957,
Dundee joined and Lake Forest and Warren left. Palatine joined in 1959 but left in 1964 and was replaced by North Chicago. The league's alignment was stable for 10 years until in 1973 when Woodstock left and the league readmitted Lake Forest plus newcomers
Crown and Mundelein. Dundee left in 1976 and Barrington in 1977. In 1978, Crown, Crystal Lake and McHenry left to charter the new Fox Valley conference and only
Maine North was found as a replacement that season. The following year 1979 Fenton, Niles North and West Leyden joined the league. In 1981 Maine North closed and
West Leyden combined its athletic program with East Leyden. Stevenson joined in 1982. Antioch joined and Warren rejoined in 1983. Niles North left in 1991 and Fenton in 1995. The league added 4 schools in 2000 and divided into two divisions. Existing members Antioch, Lake Forest, Libertyville, Mundelein, Stevenson and Warren formed the Lake division and existing members North Chicago and Zion-Benton were joined by newcomers Grant, Round Lake, Vernon Hills and Wauconda in the Prairie division. In 2005 Lake Zurich joined the Lake division and Lake Villa Lakes the Prairie division while Antioch and Zion-Benton switched divisions. Waukegan will join this conference in 2016.