It was my understanding that the YC-backed company Standard Treasury (acquired by Silicon Valley Bank in 2015) was trying to do this. I don't know where they went with this or what happened (although I believe there was techcrunch write-up about them and the purchase by SVB). Hopefully you can make this work securely because having to navigate a shitty branded (which apparently means constantly changing) web interface to monitor and move money is increasingly frustrating.