The import of IBGE data continues, though I have made good progress the last few days. I have completed importing all municipalities, and in addition to creating the necessary relations on admin_level=8, I have also created all relations for mesaregions (admin_level=5), metropolitan areas (admin_level=6) and microregions (admin_level=7) for the entire state. I have now started to look into districts (admin_level=9) and suburbs (admin_level=10) for Vitória, the state capital, and will look at continuing this with the other municipalities of Grande Vitória metropolitan area. I think I will do all admin_level=9 first and complete with admin_level=10 after that.

I have however encountered a problem, the IBGE shapefile I use as source have also a tag SUBDISTRICT, in other words, something between admin_level=9 and admin_level=10. Maybe admin_level=10 for Brazil should be shifted to admin_level=11 in accordance with the German suggestion on boundaries=administrative, to make place for SUBDISTRICT as admin_level=10?

Currently the Brazilian tagging scheme for admin_level is:
admin_level=2 : National border
admin_level=3 : National regions (i.e. Nordeste)
admin_level=4 : States
admin_level=5 : Mesaregions
admin_level=6 : Metropolitan areas
admin_level=7 : Microregions
admin_level=8 : Municipalities
admin_level=9 : Districts
admin_level=10 : Suburbs (known as bairros)

Suggesting move:
admin_level=2 - admin_level=7 : as is
admin_level=8 : Municipalities
admin_level=9 : Districts
admin_level=10 : Subdistricts ::: squeezing this one in between Districts and Suburbs
admin_level=11 : Suburbs (known as bairros)

I will bring this one up on the Brazilian mailing list.