Microsoft announced the release of System Center 2012 R2 Preview bits at TechEd Europe 2013, but they announced the preview software as an entire suite, not separate products. Now, the VHDs have become available for downloading the products in the suite separately, so you can choose to download one or many.

Here's the links:

System Center 2012 R2 Preview Operations Manager – Evaluation (VHD)

System Center 2012 R2 Preview Orchestrator – Evaluation (VHD)

System Center 2012 R2 Preview Service Manager – Evaluation (VHD)

System Center 2012 R2 Preview Data Protection Manager – Evaluation (VHD)

System Center 2012 R2 Preview Service Manager Data Warehouse – Evaluation (VHD)

System Center 2012 R2 Preview Configuration Manager – Evaluation (VHD)

System Center 2012 R2 Preview Virtual Machine Manager – Evaluation (VHD)

System Center 2012 R2 Preview App Controller – Evaluation (VHD)