I noticed just now what I suspect to be a very interesting side effect of your font size patch.
I've added custom fonts using the USE_ALT_FONTS + ;fc-cache simple hack.
With your patch I've reset font sizes removing those unuseful EXTREMELY-LARGE setting.
In the Aa dialog, after the line with official fonts, there are now THREE lines for custom fonts instead of two. I guess that being the font size line shorter, there's more place for listing custom files.
Wouldn't it be possible to set the height of the "Aa" dialog?