I definitely can confirm, that there is no prohibition on motels/hotels offering smoking rooms in Chicago. In fact, there are a few that do, but the number has diminished(sadly) vs. years ago. As far as I know, I can't think of any places in Illinois that selfishly require motels/hotels to prohibit smoking in 100% of rooms. Probably helps that IL's ban is an older one, and that it didn't pass later when this stupid idea was starting to become more fashionable to include within the language of a smoking ban.

If you want to stay in downtown Chicago, try Congress Plaza Hotel. There are a few other places that offer smoker-friendly rooms too, such as Super 8 in Rogers Park, and Heart O Chicago Motel in Edgewater. I'm surprised when I did a search that some of the places that I know used to offer smoking rooms no longer do, such as Embassy Suites Chicago Downtown and Homewood Suites Chicago Downtown. I hate the smoke-free hotel/motel room trend, so darn much!