CDH3 and HDP1.0 are the only vendor-specific distributions that are officially supported currently. However, its important to understand that this is not based on a technical constraint of the HadoopOps app per se. Some users have indeed deployed HadoopOps on CDH4 clusters already. In these cases, users rely on the power of the Splunk platform - configuring new data sources, adding knowledge objects, and creating their own charts and panels, etc.
That said, we certainly want to enable HadoopOps app deployments with a variety of server topologies in future revisions. I suggest you file a support case for this request -- I'd love to follow up to learn about your current use and how you expect this to change upon upgrade.