His latest work, My Love is soon to be released in Japan through Studio Ghibli as part of their new initiative to release between 3-4 western animations per year for the Japanese market. You can see the trailer HERE. Pay attention to the subtle expressions of the characters. It has taken 3 years to complete. No news as yet in regard to a western release.
And here is an earlier work from Petrov(1986), an adaption of Dr. Seuss' Thidwick the Big Hearted Moose which employs the same technique.
EDIT:Unfortunately this video has been removed, but as another example of his work:
The Dream of a Ridiculous Man
Aleksandr Petrov Wiki
Ghibli DVD trailer