Having "CREATE ACCESS METHOD [...] ON STORAGE|TABLE" to create a custom access method, or storage engine, and extending CREATE TABLE to be able to pass a storage method with the table definition could become a quite powerful combination. The main challenge is to come up with an interface solid enough to be able to handle problems related to MVCC, like VACUUM cleanup.
Here is as well some documentation on the matter: https://wiki.postgresql.org/wiki/HeapamRefactoring
Having "CREATE ACCESS METHOD [...] ON STORAGE|TABLE" to create a custom access method, or storage engine, and extending CREATE TABLE to be able to pass a storage method with the table definition could become a quite powerful combination. The main challenge is to come up with an interface solid enough to be able to handle problems related to MVCC, like VACUUM cleanup.