Just wondering if anyone has created a matrix that can show a metric for windows and unix servers in one column? I’m guessing some kind of JSON combo with if/null/then but I’m not clever enough to figure it out 
No don’t think there is any fancy JSON you can use for this. You can show Unix and Windows servers in a Matrix tile, but the metrics would have to be in separate columns.
I think your best bet is to look at the SQL tile.