Hey - yes, we're workig on serving map tiles. Both raster and MapBox vectors. Our current demo implementation is at https://karta.wmflabs.org/static/ - only raster tiles ATM, vectors coming in 1-2 days. The main problem, however, is budgeting - yet if we get very little hardware, concentrating on maps for apps might even be a reasonable option as apps traffic might be lower than if we exposed maps to all web users. Getting no bugdet at all is also a possible outcome, though.