I have received some questions why MDB2 does not support SQLite 3.x or why MDB2 does not provide PDO based drivers. That is actually one question as the only way to get SQLite 3.x support is to write a PDO based SQLite driver. Now this is a very important step MDB2 needs to take.
As he explains, writing such drivers would be a long process that he doesn't have an immediate need for. There is support for several databases alredy in the package, and, right now, that's just more to maintian.