Create the ability to make a custom output file size

For instance, we have a 4GB Flash drive and we want the best quality settings that will fit on a 4GB drive, it would be nice if we could select what output format we want and the program could automatically calculate the best quality settings to fit the resulting video on a 4GB drive. If we have two files, it'd create two 2GB files, etc. Ideally, it'd have a preview of the resulting video or at least a small portion available in the preview pane to help us decide. Nero Recode is an example of a program that does this.