Well it works again. But there are a couple of issues:
1. The includeOptions thing is bonkers - if you want to do weird renaming then change the key in storeMounts.
2. We do the whole descent thing through the storeMounts far too many times. It should be abstracted out somewhat (in fact, in general we could do with a far amount of abstraction/refactoring). I quite like how I do it in collectLxcPkgs - might well attempt some sort of abstraction based on that.
However, it works (again), and it's a fair bit nicer (from the end user pov) than it was before.