No, unfortunately, open-sourcing it has been on my to-do list for an embarrassingly long time.
But, building one is easier than it sounds! Think of the problem in two parts. First, find a distro used by multiple providers (we're on CentOS) and craft one script that uses each provider's API to spin up a clean machine.
Once you have that done, it's a matter of understanding your own build process, writing a script that you'll pass into each instance on creation that will fetch your source control, install libraries, and put all the pieces together.
Lots of if/else, lots of curl, lots of yum, lots of jq, but all of it is really straightforward.
Also if your providers + OS support cloud-init, then you can express a fleet of instances which run this sort of script at boot time in something like Terraform pretty easily. Switching clouds becomes "uh... what does <provider> call their <size> instance again?"
Alternatively, pre-baking cloud images that have already run such a script and are ready to boot becomes pretty easy with a tool like Packer.
Though, as the underlying OS changes, you'll need something to validate your scripts' functionality against, and a tool that's a little more declarative might make them less fragile to those changes.
Certainly understandable -- I'd prefer to keep things simple and just have some kind of validation in place rather than rely on an abstraction if I can get away with it.
Having maintained various automation over the course of the past decade and a half, I can say things do change around. Over the course of only a few years though, obviously you can stick to some LTS release of whatever you're using and be pretty confident that e.g. "some-package" does not get renamed to "some-package-version" or split into "some-core" and "some-utils", or have a package get upgraded to a version with some less-than-backward-compatible configuration options, etc.
There's nothing special about our stack. We have four different instance types (static, api, db, proxy), and we rely on a lot of the usual suspects: Apache, Tomcat, MySQL, Varnish, and HAProxy.