There is the http://www.naxosmusiclibrary.com, which is a streaming service with tons of classical. Currently 96,609 albums with 1,403,008 tracks, the vast majority of which is classical. They have 3620 albums of J.S. Bach music (and quite a few more of the rest of the Bach family). It is a little pricey, but I've always been tempted to subscribe.