The closest thing I think you will find for such is to go with SyBase's iSQLAnywhere. They have specifically picked-up and integrated their SQL database to directly recognize .DBF files. However, as others have mentioned, you'll still need to create connection to the database to get at the data. You can create a "database" in iSQLAnywhere that points to free tables instead of embedding into a single "database" such as other databases...
I've done a few DBF to sql conversions, and one approach I've done to keep the front-end consistent is to create a .PRG based set of procedures. If your app is VFP and you have private vs default data sessions throughout, any classes respect the "data session" of the form, so if you create a class under the "default" data session, then run a form that is private, then call your generic class to query and open a table, the opened table will be recognized in the "default" session and not the one of your form.
Now, that said, one other thing I did was had a single function to open the connection and return true/false respectively and allow central place to debug. If valid connection, run a given sql command. Now, if you are expecting a given "alias" name such as "person" table to be open, use the sqlexec( lcSomeCommand, "AliasYouWant" ) and much of the rest will work for displaying and editing. You would still have to push BACK the changes with SQL Insert/Update, but that is very simple with parametererized SQL pass-through.