We've published things a few times, but not anything in awhile. Our system is fairly simple, but it's probably worth documenting. We do have the stats live at monitor.red-gate.com, where the actual data is replicated from our internal systems to a publicly visible demo version of SQL Monitor.

Not sure what CosmosDB (formerly DocumentDB) would do to help us. If we removed data, we'd likely archive to another SQL Server database, and we could use distributed views to do that, but the amount of data is really small (GBs), so not sure what we'd get from CosmosDB.

That being said, I'd like to set up some project with that and experiment.