Why not use Copy Message?

Will be harder than usual because of the index saving which is special in the Index Editor.

What about a hook that rejects screwed up line endings?

What if a multiple branches or tags point to the selected commit?

SmartGit supports different SSH keys for different servers. For multiple ~/.gitconfig files, please vote for http://smartgit.userecho.com/topics/350-full-multi-profile-system/.

Quite often it happens that when I'm on develop starting something that it gets larger than initially expected. Then creating a new feature works perfectly, so I reckon it seems to depend on what branch you actually are starting to work.

You already can do that. Just select both files and invoke Query | Show Changes. You will be asked whether to "Compare with Each Other" or "Compare with Repository".

How to do that for .zip, .tar.gz?

There is already the option to just clone the last x commits.

Where you want to get this option? In the Merge command?