timmmay: Back Blaze should be plenty fast, try emailing them. They want to have you upload data because you pay for it. AWS S3 Sydney is also a fast option.
Re Back Blaze, that wasn't the experience I had, I put it down to 140ms ping, single threaded uploads per file when using MSP360.
Sure if I had 30 files being uploaded at once, I would hit 50Mbps. But during an incremental upload, involving a 60GB image file, it was hovering around 20Mbps if that.
What's your secret?
Plus, I found that Google storage had comparable prices per GB for what I needed - Sydney@ $0.0025 per GB vs $0.005 for B2.
(Singapore archive storage is $0.0015 per GB)