<p>What we are looking for is: while compiling the same configuration, say Release|Win32, is there a way to only do the postbuild steps sometimes. Like, if I am on a dev machine do all the post-build steps or if I am on a build server then don't do them. Or is the only way to accomplish this is by implementing a new configuration?</p>

<p>Commenters: Thanks for the ideas, we do not want to use scripts as they would be one more thing to maintain, and going to MSBuild proj files would be a lot of headache at this point as well. Thanks for trying though.</p>

If you want to crack into MSBuild itself (.*proj files are essentially just MSBuild scripts), you can run machine-specific steps post-build:
http://flimflan.com/blog/MachineSpecificTasksWithMSBuild.aspx
"This takes advantage of the fact that all environment variables are immediately available as properties in an MSBuild script; and that all Windows machines (that I've worked on recently) have the COMPUTERNAME environment variable set."