Hi geocoder,
Currently no.
Scheduled backups is currently unimplemented in the OS v1.0 API. Backup schedules have been dropped from the v1.1 SPEC and it remains unclear whether this will be implemented as an extension or added to the API in some other manner.
While not automatic (via cron or whatever) you might check out the /images API which does support snapshoting running instances. I think this only works with some Hypervisors (XenServer for example) using the OSAPI. Checkout the POST to /images in the OS API's.
Hope this helps.
Dan