I'm using FMPRO 11
I know I could create a report based on ROOM SALES to show all the room sales for a given month, but I want the report to be based on the ROOM TYPE instead of room sales.
There's no reason your report based on Room Sales can't do that. You can perform a find for all Room Sales records in a given date range for a given type. You can also find all room sales for a specified date range and then sort by room type to group your records by type.
The fact that the type is likely stored in a separate related record does not prevent you from using the data in that field as find or sort criteria for this report.
What I'm seeing in the picture is a list view of all the rooms, based on the rooms table.
Then in the body part of the list view you put about 31 portals and use portalfilters to determine what data you see in them.
Then you use conditional formatting to get the red fill.
Try out this file as an example of that technique: