While far from comfortable or user-friendly, users can save in-place components as real families by grouping them inside the in-place editor and exporting this library as a .rfa file. This is especially handy when working on machines that have no family templates installed. As far as I am aware there is no way to do this when dealing with annotations.
The idea would be to give plain text notes (TX) a context menu entry that allows saving them as a generic annotation family picking units, line types etc. from the file where the command is called. Thinking about it this might include other detail elements such as lines or regions.
