Hi there
Fairly new to Kdenlive, not sure if it is the right place. Anyway..
Here is the situation : we developed a plugin for Cinelerra that I'd be glad to be ported to Kdenlive if a coder feels like it (I am not a coder)
What it does : gets some Tiff files in 16 bits /pixels from negative film scans and computes the reversal picture.

Here is an example on 16 mm Kodak 50 ASA

http://www.flickr.com/photos/filmtransfer/6252200648/sizes/l/in/photostream/

The negs are scanned as they are on a white light with the typical orange colour.
The trick is of course to get rid of this dye.

It is based on this project, itself based on ImageMagick;
https://sites.google.com/site/negfix/

It works fine for a single frame but not for a sequence of individual frames as one would do for colour correction anyway.

You can find the code for cinelerra on
https://github.com/Pluies/C41

At the moment it works with floating point numbers and does not have any OpenGl support.
Just my 2 cents but I think this will appeal to a lot of people even if film as a recording media is on the way down.
And even so; there is still a lot of film to be remastered.

So if someone is interested in recoding for Kdenlive, feel free to contact me for further details.
Cheers
Ed.