I'm starting work on a new site (8.x), and I'd like to be able to eliminate downtime if possible during production deployments.

What are my options for keeping my Content Delivery environment online during deployments? Code can often rely on content, so I typically end up with a delay while I wait for content to publish.

Assume a separate CM server and two CD servers behind a load balancer. I've mostly used TDS, but am looking at Unicorn this time around as well (In case that's important to the solution). I'm hosting on Azure - but I'm looking for Sitecore specific details.