I finaly completed the script for model simplification. It removes redundant faces, vertices and edges. Some small things need to be added yet, but it is working good now, so I thought I release it.
It’s mainly usefull when working with boolean operations and extruding curves.
You can download if from
http://nyoxi.mysteria.cz/eng/blender.php
It works good! And nice gui and progress bar!
I like it! It’s a nice simple tool and well made. It looks like the new 2.28 API has brought a great growth in Python development. Very exciting!
edit:
hmm… I noticed in some experiments that it ‘fakes’ ngons. This may be ok in some situations, but it may cause problems if you want to use subsurf, or edit the mesh later (eg. with proportional edit). Would it be possible to have an option to either fake ngons, or just quadrangulate/triangulate?
Here’s a pic to show what I mean. The original plane was subdivided and beauty subdivided a few times, then had the script run.
Nice script and very nice GUI.
I was playing around with a script that identifies co-planar faces in a mesh, though I hadn’t got as far as working out how to remove them.
I’m happy that you found it usefull. 
I know that I must improve it’s fuctionality much more, because in some situations it’s not so succesfull as it should be.
And a little note, if you downloaded the script before 0:56 08/08/03 than it prints lot of debug stuff that is not needed. So comment the lines that do it yourself (they are two) or redownload the script again.