Hi Julius,
I once did it this way
- Vendor.Base - Package containing the base (layout, nodetypes, fusion etc)
- Vendor.Denmark - The site package used for the Danish, requring the other, and including the Fusion
- Vendor.Germany - The site package used for the German site
- Vendor.Sweden - The site package used for the the Swedish site
So a base package for the things used on all sites, and a site package for each language/market/domain