In linux land, there is Teleport, which is relatively new. There are probably some other options, but I liked the POC I did with teleport, it just needs to mature a hair.
In windows land.....I've got nothing, hence the problem.
The problem is big enterprises need support agreements and the other typical enterprisation features. An open source project alone will never fit most enterprise's appetites, especially for something as important as security/auditing/compliance. You at least need a company behind the open source project willing to provide enterprise setup and support.
