Yes, absolutely. This is a very common use for our DNS Failover service. While some customers use it to switch between servers at different datacenters, it works very well to switch between the same server that has two different public IP addresses at the same location or datacenter (e.g. two ISPs, two WAN connections etc.) DNS Failover doesn’t know the difference, and even if it did, it would think this type of implementation were a great idea!
Our Cloud Load Balancer can support the same concept too.
Here is a video that covers creating monitors that you may find helpful: http://totaluptime.com/creating-and-managing-monitors/