Q-Views is a module I came across while browsing through new modules on drupalmodules.com.

It's been a while since I've been so impressed with a module. This allows you to create views based of SQL. You allow it to analyze your SQL and it will populate a list of options for each field your query returns.

You can write module hooks to handle the query output on a per-field basis, or you can write the handler directly in the configuration.