I know of a few teams over the years who have had a large winning streak which i would classify as being 4 or more successive premierships. A few that i know of are Ramblers in the River Murray Football League who won 5 in the late 70's, Victor Harbor 6 in a row in early 90's(thanks largely to their Glenelg/SANFL imports). The most of i know of though are Ramblers (Cummins) in the Great Flinders Football League who i think won about 11 or 12 (maybe more) leading up to early 80's.
Does anyone else know of any large winning streaks in country/regional/amateur leagues?