About 10-15 years ago, something a bit like this was happening in the mobile phone network market. My employer did a project for a big mobile operator to build a white-labellable web platform for selling phone service. The idea was that they could launch a fully operational new phone brand with the click of a button. They could use this to target different market segments (eg a low cost no frills service, without dropping the prices for their main brand), or to form branding partnerships (eg with luxury brands, football clubs, etc).
At least one of the brands is still running, but I'm not sure the co-branding thing ever went anywhere.