Change the file extension of the selected files

I have a renaming problem:

I've got folders/books which consist of many little files without an extension (but in fact they are valid XHTML) and these files are already linked between each other (for example index_file points to sec1_file & sec2_file; sec3_file_chapter2 links to sec1_file etc.)

When i import these files into Calibre Ebook Editor, they end up in Miscellaneous folder. So i add XHTML extension to these files outside of Calibre and import them this way and they show up in Text.

But for links to be working, i need to then rename them back inside the Text folder to files without an extension sec1_file.xhtml to sec1_file. If i do that one by one, it is very time consuming, but the result is excellent.

Suggestions:

• In the "Change the file extensions of the selected files" dialog - ability to remove the extension (when the "New file extension:" is empty, it removes the extension), or
• Leverage "Find/Replace" dialog for "Bulk rename the selected files", there could be another option "Filenames" in "Where to search/replace" dialog.
• Ability to drag and drop from Miscellaneous to Text