Linux NAS HowTo suggestions?

Hello -

I'm looking for a VPN/NAS howto guide or solution that you can recommend. I've looked at FreeNAS, and am considering it, but not sure it does everything I need.

Scenario: We are looking to build a NAS in our office from a linux machine on a limited budget.
Our office is behind a router with NAT from a single IP that is also a NAT address.
ie - public IP is 2 routers away, one I control, the other I don't.

These are our primary requirements.

1) VPN from home(anywhere) into office to access office folders.
2) SSH from home(anywhere) to access the machine.
3) Allow SSH/RSYNC backups from other servers (remote webserver backups)
4) RAID with mirroring at a minimum (RAID 1 or RAID 1+0 or RAID 5+1)
5) Firewalled to allow only SFTP, RSYNC, SSH, VPN and SAMBA access

Is this just a matter of installing my favorite linux distro, and installing/configuring the proper software (SSH, RAID, SAMBA, IPTABLES, etc)?

Or is a complete solution like FreeNAS the way to go?

Thanks,

Matt

PS my Linux admin skills are intermediate level, so I can figure out most things if I have a good direction of what to do.

Try GlusterFS. It is very easy to configure. Here it is:

Gluster.org Community Website | GlusterFS is a cluster file-system capable of scaling to several peta-bytes.