I have heard that the Supercharger sites from Denver to St Louis will be as follows. Denver is supposed to get a permanent Supercharger site, hopefully west of the I-70/I-25 interchange, but I have not heard anything about St Louis, itself. See
Denver, CO to St Louis, MO - Google Maps for reference; the Independence location is only an intelligent guess.
Denver, CO
Limon, CO - 89 miles
Goodland, KS - 109 miles
Hays, KS - 144 miles
Salina, KS - 97 miles
Topeka, KS - 111 miles
Independence, MO - 74 miles
Colombia, MO - 115 miles
St Louis, MO - 125 miles
If these rumors that I have heard pan out, it will be a very nice, well-spaced set of Superchargers along I-70 between Denver and St Louis. The only site that we have real confirmation on is Goodland, KS, but keep an eye out at the other locations. I hope these all get installed by the summer!