Hi! I'm looking to supply a custom identityfile to ssh. It looks like the ssh command is hardcoded in attic/remote.py and at the moment it's not possible to add custom commandline to the invocation of the ssh binary (correct me if i'm wrong...)

Would it be possible to add some e.g. --ssh-command option, so that i can write e.g. --ssh-command="/opt/my/custom/built/ssh -i path/to/id_rsa -o foo=bar" ?

I guess it would be currently possible to workaround by hacking $PATH and pointing ssh to a local wrapper script... but surely custom identity files and other SSH options are common enough to warrant having this in the core (e.g. rdiff-backup has --remote-schema)