Guesstimate [1] (cited in this paper in footnote 6 and previously discussed on HN [2]) is a really nice implementation of some of these ideas.

Has anyone come across other good implementations?

As a side note, I've been doing more probabilistic programming with pymc3 recently, and it's pretty incredible how leaky the abstractions can be. I'm not saying there's a way to do better, just that at present there's a huge gap between the beautiful vision of "the inference button" and the current tools.

[1] https://www.getguesstimate.com/

[2] https://news.ycombinator.com/item?id=18785371