With that said, I'd love to see the Scala equivalent of this - the Scala plugin for IDEA works fairly well (they still have quite a few problems with inline error highlights/parsing when your Scala code uses path dependent types), but the Typesafe official Scala IDE uses Eclipse, which utterly rules it out as far as I'm concerned.
A lightweight but functional Scala-native IDE with builtin sbt support would be absolutely awesome for a pure-Scala project.
This would indeed be wonderful. I have been using Scala as my first language of choice for some time now and personally feel that Scala is still held back a bit in terms of tooling. Please consider this!
I am a big fan of IDEA and use that for Java and Groovy, and also Jetbrains' AppCode for Obj-C development, but the Scala support in IDEA is currently just not good enough.
I don't even think the full switch can ever be made. Because it's Apple development, everything is in an "Xcode project" (instead of, say, "iOS project"). So even using AppCode I'm still dropping back to Xcode some of the time.