I've created a GPLed project that converts SNMP walk data into a Zabbix import file.

https://www.zulukilo.com/svn/pub/walk2zabbix/

I've also created a Python library that can be used to create Zabbix import files. It's also a dependency of walk2zabbix.
https://www.zulukilo.com/svn/pub/importfile/