What I was referring to was also the pixel & font sizing based on the platform. The default font search stuff from extended is in vanilla, at least in the tk side of things AFAICT. Monaco is the default on OS X because it’s pretty much guaranteed to be there. Deja Vu is not, but I would think the font search would check for that first…
If you only want that font, it shouldn’t be too hard to change the defaults. Perhaps a better solution is to ship with the font itself on Win/Mac. I do this with PdParty on iOS which displays using Deja Vu Sans Mono ...