Devs doing QA worked fine for us. You need to have a team that actually cares about the product, and you need figurehead devs - not necessarily seniors or team leads, but charismatic people others will fall into line with - who model the behaviours you want.

The problem with almost anything else is that it increases the number of hand-offs between groups of differently-aligned people on the route to production. If you're aiming at multiple deployments per day, with sub-hour commit-to-prod times, the latency in those hand-offs adds up way too fast.