A pip install-able conversion of Paul Durrant's kindlestrip library to strip the penultimate record from a Mobipocket file. (http:https://www.mobileread.com/forums/showthread.php?t=96903)
To install:
pip install kindlestrip
To use:
$ kindlestrip input.mobi output.mobi
$ du -sh *
268K input.mobi
200K output.mobi