Wondering if Splunk integrates with or supports Windows SCOM also if a Splunk for SCOM App might become available soon.
Depends on what you mean by "supports". In the past, Splunk had a "right-click" integration from within System Center where some key and value (server name, IP, etc) was used to open an IE browser with a pre-populated Splunk web search URL. This was mostly done to enable investigations around pre-built SCOM views.
In regards to a SCOM "app", don't expect that any time soon. You can however use PowerShell to wrap Splunk's APIs to bring in data into custom views.
If you're referring to indexing the data that SCOM lives on, you can easily use Splunk's WMI input to capture the same Event Log or "perfmon" data.