It would be nice if there was a feature to allow changing the aperture during exposure. This should allow for creating an effect similar to using an apodization element, resulting in smoother background blur. If you could choose a curve of the change between the starting and ending apertures, that would be great.
You can see an example of an apodization filter hack (using a piece of film placed behind the aperture rather than controlling the actual aperture) here: http://www.4photos.de/camera-diy/Apodization-Filter.html
I'd also be glad to see such a feature, if technically possible... on any ML-compatible body?
(for my part, I own a 50D)
PS: I know this is my first post here, but I'm a long-ago very glad user of ML :)