Looks interesting. Once this is finished, let me know and I can distribute a link as part of the MD_Parola releases. If you find the tool useful chances are others will also.
Just to let you know that there is a command line version of the font builder that does not use MS Office. takes a text file as input and outputs the font .h file. It is referenced/explained in the online docs and also explained in my blog at Parola A to Z – Defining Fonts – Arduino++.