This document lists some problems I encountered using s3cmd on rsync.net and how I solved them.
s3cmd sync doesn't support the --storage-class argument, and even that doesn't support the ONEZONE_IA
storage class. You can still upload objects to that class by specifying the x-amz-storage-class header,
but s3cmd sync will ignore that. The best solution I have is to upload your files as you normally would,
then use s3cmd modify to set the storage class after upload.