My company (Singlebrook) built a PT workalike that works really well (in my humble opinion - ha). We're only using it internally and with our customers, but we use it every day and are really happy with it. It's not a feature-complete clone, and we don't intend for it to be, but we've probably built 70% of the features and have covered all of the basics of the project UI.

We haven't been planning to release it commercially, but if you're interested in trying it out, please reach out via singlebrook.com/contact and I'd be happy to set up a test account for you. If you happen to really like it, we can probably figure out an arrangment for you to use it.