I handle edition info by manually appending it to the title (3rd Ed.) and manually putting correct edition date in the Published date field. Another possibility is to use a custom column for edition number, and one for edition date. Metadata Download date data and edition number often have to be corrected manually, which for accuracy usually means manually checking title page or copyright page inside that particular book format.
EDIT. There are several problems.
1. The data at the Metadata Download source may be inaccurate.
2. Varying Metadata Sources seem to handle edition data differently or not at all.
3. So calibre determines what date to select from all the metadata source returned data. Even if programming for that determination could be improved a little, that wouldn't solve the first two problems and the data would have to be checked and corrected manually anyway.
4. Possibly someone could write a plugin to extract the correct edition date and edition number from within the format. But edition data isn't presented in a standard way across all publishers and all languages and all book formats. So writing it wouldn't be easy and would probably take a lot of work.
Last edited by unboggling; 06-12-2012 at 05:30 AM.