System Center 2012 contained the Unified Installer tool but that tool was not updated for Service Pack 1. The tool was mainly used for deployment of labs for SC 2012. As the tool was not update for SP1 there is alternative PowerShell Deployment Toolkit. This alternative is actually a set of scripts that will help you with deploying SC 2012 SP1 from the download of the evaluation versions and all prerequisites till the actual installation. The scripts are made in such way that with some modifications can be used for deployment of other software. Download links and more detailed description can be found in these two articles:
Add/Remove a Management group from a SCOM 2012 agent with script
Two very useful scripts if you multi-home SCOM agents provided by Bob Cornelissen:
“Splatting” PowerShell script activities in Orchestrator
Robert_Hearn: “Splatting allows you to bundle a set of parameters into a hashtable and then simply using it as single parameter to a PowerShell function or cmdlet.”. To see how this technique can help you in Orchestrator read the full article here.