This is exactly what I had in mind. Thank you for taking the time to make a mockup.

This would work in the Show Changes (F4) dialog but ideally this would be how the default Changes view works.

As a clarification: I'd like to see multiple diffs in one view, but not necessarily with a 'unified' diff like in the example. That's just how SourceTree happens to display a file's diff.

Showing full files with both sides like it already exists in SmartGit would accomplish what I need if I could see multiple files at once below each other.