Turned up an article in ProQuest that indicates I-94 was originally going to use the US 41 corridor until the Tri-State Tollway alignment was decided to be close to the US 41 corridor; the shift in interstate designation occured in 1952. The US 41 freeway was going to be built with only a 50% federal match. Source article is "Plan Skokie Road Expressway A 1950 Project Comes to Life 12 Yrs. Later" Chicago Tribune July 8, 1962
EDIT Other finds:
* Another article indicates that the IL 83 corridor was strongly consider for the Tri-State; the article also mentions plans for the Tri-State to hook up with a Wisconsin Turnpike. Source article is "Sidetracks Skokie Highway Plans Toll route is cited as alternative" Chicago Tribune November 23, 1953.
* US 41 was also apparently shifted onto the Edens between the Skokie Road interchange (Exit 34A) and Touhy Avenue interchange (Exit 39). "US 41 Marked On Edens Hwy.; Aid To Trucks" Chicago Tribune August 30, 1953.
* There's a 1944 article that has two decent maps of Chicago highway plans, with the Dan Ryan along Union Street from Archer Avenue to maybe 51st Street, then curving west to follow Halstead Street to 119th Street. The Kennedy would be along Clybourn Avenue from Congress Street to Western Avenue where it then follows the C&NW railroad to Cicero Avenue. The Kennedy and Dan Ryan routes tie into the Congress Street route via a flipped over "h" shape with the western route being the longer. A bypass of the loop from today's I-55 is shown along California Avenue. East-West radial routes are shown along Higgins Road, Butterfield Road, and North Avenue, with the North Avenue route splitting west of St. Charles. Today's I-57 is shown stopping at a belt route that resembles I-294, with today's IL 394 shown extending out of the region. The main I-294 analogue is shown running through Elmhurst, the east side of Arlington Heights, and the east side of Libertyville before connecting with the Edens around the curve on US 41 in what I think is the area of Delany Road in Gurnee. There's a diagonal route running west from the Edens perhaps around IL 22 west to Fox Lake and beyond. A sort of inner loop is shown branching off the outer loop, passing east of Willow Springs, briefly merging with the I-55ish corridor, before continuing north, passing through the east side of Des Plaines and ending at the Fox Lake diagonal. An east-west route is shown near the US 30 corridor that dies out near today's I-57. Interestingly, the larger map does not have the North Avenue and IL 394ish corridors connect within the city limits to any other expressways. Source article is "Edens Parkway Is A Key Route In Traffic Plans." Chicago Tribune July 30, 1944.
* A map with an article has a giant triangle (maybe three miles to a side) shown for the interchange between the Tri-State and Edens Spur routes. "Suburbs Wait Shift In Toll Road Routing" Chicago Tribune October 10, 1954
* Apparently what evolved into I-90 was to follow the unbuilt Stony Island/Lake Shore drive route between the Skyway and the loop. The article and maps seem to have placeholder numbers for designating the interstates with the various IL routes having numbers between 1 and 14. "Illinois Using 150 Million In Road Aid In '57" Chicago Tribune June 21, 1957.
* Chicago canceled the Stony Island Expressway in late 1959: "City Changes Plans; Expressway Dropped" Chicago Tribune, December 13,1959