Maybe I should have explained better. By custom meta albums I really mean the user could create premanent meta albums based on search results(ish). So he inputs a name for the album then gives the criteria for this album such as *.mov, *.flv, IPTC=Camera Manufacturer, taken by user x etc
Uses for example, a large photography website where each month a particular photographer could be showcased simply by creating a meta album of all the images they have uploaded. Or maybe they want to show off wide angle photography so could create a meta album of all wide angle shots (taken from lens data in IPTC). Maybe a car website wants to show off all images tagged Ford.
Again, not sure if it is technically possible but would be usefull.