I think the equivalent would be a csv of your asset info so if glbse goes down share issuers have a backup. Just need to host the csv file somewhere with the file location listed on the coupon
Better, a file that states a user's PGP public key as registered with GLBSE, listing all your assets, and then clearlsigned with an official GLBSE public key.
This would allow any asset holder to prove they hold a certain number of shares. (The file would need to include a date, too.)
I highly doubt this is a new idea.