[sciurius]

There are many ways of doing this, but a widely accepted standard is defined in "Standardized Chord Symbol Notation" by Carl Brandt and Clinton Roemer, usually designated as "Brandt-Roemer". The book is out of print, but scans can be found on the internets (e.g. http://home.cogeco.ca/~douglasgifford/st...20scan.pdf).
Except for the MI/MA thing it's a good standard and I'm gradually migrating many of my chord-typesetting programs to this standard.