All those store-exclusive brands are just rebadged products by "real" manufacturers. Sometimes not even the same manufacturer.
For example, that Insignia TV Kitsunexus got is a re-badged Norcent. I have an Insignia portable DVD player with a 10" screen from Best Buy that is a re-badged something-or-other (not Norcent). Daewoo maybe, I can't remember.