Scott Fybush visited the WMVP site in 2008:
A selection from a decade of visits to tower and studio sites in the Northeast and beyond
He summarized the site's history nicely and got some good shots inside and outside the building. The second building on the site, the one in the background in the pictures, was the original TX building way back in the 30s. The great art deco building with the WCFL sign was built in the late 1940s to accommodate the big RCA BTA-50F, shops, and office space. The RCA's cabinets can be seen in Scott's pictures. The curved geometric tower displaying the WCFL calls is actually part of the original air circulation for the RCA's hot tubes. You can see the big louvered vent near the top. Form and function combined.
There used to be a metal plaque mounted to the left of the front door displaying the Chicago Federation of Labor name. I assume it was removed when the CFL sold the station in the late 1970s. The four bolt holes that held it in place are still visible when you're near the site. I've wondered what became of that plaque, as it has historical significance.
The old second building on the site was repurposed as the studio in the mid-1980s when WCFL was Christian-religious under Statewide Broadcasting. They saved money not renting studio space downtown. It was used as storage space after that.
I was able to visit the site about 20 years ago when ESPN/Disney owned it. Disney also owned WLS at the time. The late WLS CE Warren Shulz was a friend of mine and had responsibility for the Disney-owned stations in Chicago. Warren showed me around the site, which still had the the gutted BTA-50F's lovely cabinets, the dusty remains of a machine shop, and a reception area inside the front entrance. An enormous squirrel-cage fan sat inside the base of the big vent stack, though it had been quiet ever since the old RCA was taken out of service.
It'll be a real shame if the building comes down after the TX moves to rural Joliet. I just hope what's memorable, like the big metal WCFL sign, are saved someplace where it can be appreciated for its history