Posting this picture filter here specially because it's very rare and difficult to find picture filters made as plug-in for Gimp coded in Python - publishing this would be also for encouraging people on enrich Gimp with good filters (better than mine one, please! :-D )
The only problems of this filter is it seems to be somehow slow (even having a simple code), wich takes 20 seconds with a 320x200 picture - it's also missing undo and progress bar while running...
I noticed that the scanlines script-fu was not present anymore, so I cooked up a new one. This one is completely self-contained. Has a few enhancements to it, making it easier to work with. Thanks to Federico Mena Quintero for his work on the original "Erase Every Other Row" script-fu which served as part of my guide.
The script-fu will install in "<Image>/Script-Fu/Enhance".