This script can smear frames using a lattice, it’s available here. Keith Osborn has a demo of the script in action using his free Mr Buttons rig below.
Video tutorial:
boSmear script:
http://www.bloomsbury.com/cw/cartoon-character-animation-with-maya/student-resources/maya-scripts/
The boSmear script is written by CTO of Moonbot Studios Bohdon Sayre.