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.
Actually I think it would not even take very long to write such a driver as PDO does alot of the work in the core driver (like prepared queries, error code handling etc) and all the modules mostly do not rely on functionality outside of the core driver. Furthermore the MDB2 API has seen a lot of changes towards making things more compatible with the PDO API.
However I personally do not have immediate needs for PDO based drivers nor SQLite 3.x support and I am already maintaining a ton of drivers and other PEAR packages. I am here to lend a helping hand, but unless other people step up and help out I will spend my time on other things.