If that was the case for C#/.NET, they really didn't have much to show for it at time of release. IntelliJ IDEA that came out a year later was a fancier, more 'integrated' IDE.
But beside smalltalk, there were lots of others. All the commercial Lisps, Dylan etc. Somewhat more mainstream-ish - the NeXT Objective C environment is a good and much earlier example.
There were lots of interesting things about .NET when it came out, the IDE-ness of it doesn't strike me as one of them at all.
