I'm also thinking about this again right at the exact same moment :).

The issue for me is that I'd like to apply this to all sorts of presentations e.g. also lists and tables.

How about adding a #fixed property to GLMFormattedPresentation that the user can set and making the existing renderers respect that?

Just now my work-around has been to add a "copy to clipboard" action to all my presentations since they are unreadable in the GUI :-\