Marijn,
I was talking with a friend about Submarine and Postmodern and he complained about the fact that Postmodern (and thus Submarine) are PostgreSQL specific. I agreed that this is a shame: for some smaller projects Postgres is a bit overkill and you may want to use something smaller, like SQLite.
You write in your docs that "...postmodern has no intention of being portable across different SQL implementations (it embraces non-standard Postgres features)." What do you mean by that? Is there anything Postgres specific outside of CL-POSTGRES? How difficult do you think it would be to port Postmodern to SQLite? (And: how long did it take to write CL-POSTGRES?)
Cheers,
-- Richard