You can use a simple Expect script to backup all the configurations using either FTP/TFTP. Cisco Security Manager (CSM) automatically does configuration management if used.
Logic of the scripts could loosely be
a) Login into the admin context/switch
b) Save all the configs "wr mem all"
c) Get a list of all the configuration files, either "dir flash:" or "show run | inc disk:" would give you the file names.
d) Parse the output from above and backup using the following syntax
SSystem Configuration:
copy /noconfirm running-config tftp://x.x.x.x/backup-running-config
Context Configuration: Repeat the command for each context configuration file
copy /noconfirm disk:$Context_file.cfg tftp://x.x.x.x/$Context_file.cfg
disk:$Context_file.cfg
FTP syntax:
copy disk:[path/]filename ftp://[user[:password]@]server[/path]/filename
TFTP may not be good for large config files and FTP would be a good alternative.
Hope this helps !