Multiple IPv4 Endpoints

[kaerast]

Hi,

We're in the process of setting up an office network with internet connections from two different ADSL providers for failover purposes.  These will be cheap business grade connections so we won't get any BGP (at least not externally).  We intend to set up the outgoing traffic in a load sharing with failover configuration using a Netgear SRX5308 router and will have multiple Centos servers internally.

How can we configure Tunnelbroker.net to handle this situation?  Is there a better way of getting IPv6 connectivity when our ISPs don't support IPv6 yet?  Would it make sense to use IPv6 internally only in this case?