How much data such a script can handle only the author of such a script would know, and it wil also depend on the server configuration probably.
Some people have also reported success with these scripts, you can try until your find one that works for you:
MySQLDumper:
http://www.mysqldumper.de/en/index.php
MySQLHotxcopy:
http://www.vbulletin.com/forum/showt...t=mysqlhotcopy
Bigdump:
http://www.ozerov.de/bigdump.php