This is wonderful!

But does anyone know how to figure out what the DATA_COMPRESSION setting is for a given index (none, row, or page)?

It doesn't appear to be in sys.indexes or the most common property functions; the closest I've seen is compressed_page_count in sys.dm_db_index_physical_stats with 'SAMPLED' or 'DETAILED' level (clearly a bad idea to use on a large database).