Converting shared fields into local fields

We have decided that shared fields are more trouble than they are worth, especially when you want to apply validation rules to locals instances of shared fields, and also because it complicates/doesn’t work with MSM.

Has anyone managed to convert their shared fields into local fields, preserving the content already stored in the shared fields for content items previously created? Is there an easier solution than manually recreating local fields with the same set up and the shared ones, then manually recreating content items, their relationships, etc?