In order to faciliate easier connections to a Microsoft Access DB why not allow ODBC connections to use a connection string rather than a DSN? Trying to create DSNs for each Access DB when you have a lot of dynamically generated ones is a pain, and if you could do something like:

odbc_connectionstring_pconnect( "uid=myname;pwd=mypw;driver={MSAccess};server=myserver;database=pubs;dsn=''" );

that would be great.  It would also allow for PHP to connect to different types of servers on the fly without any prior knowledge of the server existing (and having a DSN) before.