Open-source library request: A library that lets you use S3 and Google Storage Cloud simultaneously and fail-back to another if one have problems. There are many use-case when paying 2x for storage is a reasonable tradeoff for higher availability and also be provider independent.
Importantly, make sure you CNAME your bucket under your own domain so that you can switch services.
edit: Much easier than AWS Lambda, actually: http://aws.amazon.com/about-aws/whats-new/2015/03/amazon-s3-...