It should be pretty easy to look at the approach I took and mimic it for other providers. I write Open Source code for Microsoft, so we made it work with Azure first - but the code should be clean enough for someone else to pick it up and work in other stacks.

I should probably also mention that the engine running Azure Websites is open source itself (https://github.com/projectkudu/kudu), so you could just point it to your own engine.