Multi Wans - Dual routers - Carp

[bgibson]

Good afternoon,
I was curious to know if anyone has ever setup two routers, one with one wan, and another with another wan and was able to keep carp to where if router 1 wan goes down, it fails over to router2. Below is our current setup:
WAN1 - Level3 - MPLS network. we want this to be a direct connect not using a VPN.
WAN2 - TWC - OpenVPN.

We are having issues with routing these two while on the same box, so we wondered can Router1 be setup for the MPLS network, while Router2 is setup for the OpenVPN in standy by not routing. I wasn't sure if this would even work since the wans are not carped and if it went down, the lan would still be active on the router1 (if it was just a wan issue and not a router turned off).