cloning the block layout and other display settings

Problem/Motivation

I have an existing theme, created from the default AT Theme. I've set it up with laying out various blocks. I use this theme for a few sites. Now one of the sites needs a slight modification, that is just local and shouldn't be reflected in other sites that use the same AT-based theme. I created a clone and set it up as the default theme for this site, but it turned out that none of the blocks I had in the original theme is there, so I'd have to repeat the configuration, which may be time consuming as there are many blocks.

I understand that because, in general, different themes have different regions, and, therefore, cloning blocks and their associations with regions makes no sense, but in this case, where we are *cloning* the whole theme, it may make far more sense.

If this feature is already available, what do I need to do? If not, do you think it makes sense to add it?

Thanks

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes