Sync file data between two servers without VPN?

Is there program or utility, or some method to copy or sync data between servers where they are not connected via LAN?

There are LOTS of great file sync utilities out there, unfortunately, you need to be on the same network for them to sync up.

The deal is, we have two servers that have a large amount of data (8TB, 13 Million+ files) at two different cloud providers.

We're looking for a way to sync up data between the two servers. In this particular instance, VPN is NOT an option as we are working with cloud providers, and one of them doesn't allow for opening ports, unless we pay them $500/hour to do so. Our experience with them has been that it takes several weeks, and multiple $500 costs. (I'll put it this way, don't ever go with Visi).

What I'd like to be able to do, is use a utility of some sort on the source server (Windows 2003 32 bit) and sync up the data to a destination server elsewhere on the internet. Data would need to to travel the public internet to get from the source server to the destination server.

Keep in mind, we have 13 million files. If it takes a month to copy, that's ok.

Web and FTP ports are open on the source server.

Any good ideas?

Thank you in advance!