Was able to work through an interesting content deployment issue on a medium SharePoint farm with the help of the following kb:
All Content Deployment Jobs were failing and the error in the event log indicated a 404 not found. Which doesn't make a lot of sense since the deployment was not to a separate farm, but to a web application on the same farm.
By setting up the trace log on the SharePoint Services Timer Service on the Central Administration server of the farm, I was able to see that the url for the publishing web request included the server name. It turned out that the team that set up the SharePoint farm created a dns name for the Central Administration server, and deleted the server:port entry from the Alternate Access Mappings.
Tried re-setting the Alternate Access Mapping for the Central Administration server back to servername:port, but this did not solve the issue. Used psconfig to unprovision then reprovision Central Administration with default settings (servername:port):
and that solved the problem - all of the Deployment Jobs now work perfectly. There was one Deployment Job between farms that was also not working, and the target farm was built the same way. Unprovisioning the Central Admin on the target farm and then reprovisioning it cured that cross farm deployment job.
Sounds like a big deal to blow away the Central Admin web and then recreate it, but the psconfig tool makes it quite simple and painless.