Here's what I want to do:
This is for a TeamCity build and release that I'm trying to configure in a single step. I could create a custom build file but I'm trying to tackle this without adding any additional configurations to the app.
There are a lot of examples around of MSBuild parameters which can do this publishing via WMSVC - here's a great one - but that's not going to play ball with IIS 6. Are there equivalent params which can be used when there is a dependency on MsDepSvc? Is this even possible or am I left with either a custom build script or a package build followed by a publish build?
You can modify an existing .csproj file to add any additional target needed (it's just an MSBuild file) and publishing to an IIS6 server can be done via different MSDeploy providers (webServer60, metaKey, or contentPath via a share).
While this would be possible to do by adding a Target in the MSBuild of your project, I'd recommend that you split these two activities out into two separate targets. By splitting them into two separate targets you can still call them together msbuild /t:Package;Deploy
but you can also call them independently.
This would allow you to create a deployment package and have TeamCity include it as an artifact of the build. You could then download this package from TeamCity and deploy it to any server independently, even if you deployed it automatically. If TeamCity also creates your release builds, you know have your production deployment