For rewriting articles, you want a text editor that can load two versions of the same file and compare the differences. Load original in left hand pane, and th new version in the right hand pane. Make as many edits as you want and you can see the differences highlighted.
I use it for checking differences between current and older versions of the source code to my programming projects. Works great for article rewriting though
I would recommend some programs but the trouble is I cant think of any names off the top of my head for Windows though (been a long long time since I used anything from Microsoft including Windows....).
Have you guys heard of the software from translatedotnet? It doesn't rewrite but translates, and the trick will be, gather a german or french article, then translate it into english. It's more than rewriting :-) You'll have a fresh article...