I've just committed changes to the source code repository that allow you to export query data in csv format from our built in query tool. So you can write any query against any table(s) and export the data.
I also added support for exporting verified newsletter subscribers on the page that shows newsletter subscribers.
Don't know how well it will work if there are hundreds of thousands of rows, probably would have to do it directly using sql server in that scenario but it should work well for reasonable amounts of data.
Hope that helps,
Joe