We have iZotope's pitch and time stretching algorithm. I think it would be great to also have iZotope's sample rate conversion algorithm.
When importing waves, we'd now have iZotope quality SRC. When exporting tracks, we'd now have the ability to choose a new target sample rate.
I think it would also be great to have the ability to change an entire song's sample rate within a project. Does any DAW currently have this ability? A simple option of 'change projects sample rate' and then select your target sample rate, choose your iZotope SRC settings and then wait for the program to render the clips in the project.
Example 1: You are mastering or doing fades for your final 48kHz - 192kHz mixdowns in Sonar... you now wouldn't have export files, then leave the project and use a high quality external sample rate converter and then reimport the waves into a new Sonar session. You could simply convert the project and then you'd be ready to do your final processing and export for CD or MP3.
Example 2: You're mixing a clients album that was recorded at 44.1kHz, but you prefer to mix at a higher sample rate because your plugins sound better (less digital aliasing) at a higher sample rate... Or your converters sound better at a higher sample rate when running through your external analog summing mixer. You could simply convert the project to a higher sample rate, save and you'd be good to go.