Gûrig and grad/gorod look and sound quite different to me.
I am just telling why it is better to avoid any GR.. word as the connotation for Slavic speakers are very strong for this particular stem (actually German "Grenze" = border comes from it, too) - as such I am just commenting on your suggestions.I don't have any problems with that, anyways it was just a suggestion...
*shrugs* i thought we were looking for an easterling term...