VPN Bonding
From BE Usergroup Technotes
Does your server in <Insert data center name here> have the ability to have a spare (or two if you don't want double-nat) ip and can it run vmware server?
If so that's the server side happy.
Secondly do you have a machine in your house that can run another vmware virtual machine to do the vpn bonding..
You then need a "load balancer" (another machine running pfsense or zero shell) to split the two vpn streams down each line [so that machine needs two NICS].
Thats the most challenging part - the rest is configuration which is easy now I can tell you what I did ;)
My setup is based on ZeroShell.