To answer the question, there isn't a book or project on St Louis in the works, though it would be a great community project, if your up to doing it yourself. If you'd rather not do a whole write-up on the STL sprawl, I'd love it if you wanted to add a few of your favorite "Places of Interest" to the
Target: 2070 project.
On the STL interest to shadowrunners, the big game will be between nationals - corporations too small or weak to compete in the megacorp game, but protected by politics and nepotism inside their respective nations. When the nations spilt, a lot of companies became multinational overnight, stripping them of government protection, leaving them naked to megacorporate interests. Breaking the company into separate entities would protect them, giving them recourse with national courts, rather than the Corporate Court - who has no time for meager A rated companies. So your research division across the river is now a separate company from your manufacturing. Which gives you a little resilience against scandal - scandal is much more damaging to national companies. Nobody punishes other Aztechnology brands if StufferShack Nukers are contaminated with psimonella, but poisoned Busch Light will hurt Budweiser and Bud, if not the entire beer industry (meh, people would probably switch to import before giving up beer).
On the Tri-City Port - it's important. When Chi-Town went down they built ports in Gary and Milwaukee to keep goods flowing into the UCAS. But these ports were overburdened, which means goods coming up through STL, and still coming down the Muddy River, too. It's going to be a corp port, though, surrounded by automated factories. You'd have raw materials coming in from the CAS and UCAS, processed in STL and the ported out the port. I'm picturing constant zeppelin and drone trucks coming in and out of the place.
I imagine a massive multicompany project on deepening and widening The Mississippi, north and south would be going on, based in STL. Maybe they turn the toxic silt into a plascrete filler in low-income housing? Roads, perhaps? Or maybe they just dump it, and people "silt dive" for food and buried treasure. Anyways.