We are checking our Bamboo configuration into perforce as a precautionary measure. What we currently do is export the full config, then delete everything but the administration.xml and administrationConfiguration.xml. We check these two files into Perforce.
The administrationConfiguration.xml still has a lot of things in it that it looks like are not needed for the minimal configuration to restore a system.
It would be nice if there was an option to create a 'system restore' backup - not a full export. I think you get this when you do an import - it makes a backup, so if that could just be made an option on export, that work fine.