funkjames

VMware workstation can be modified using an enabler to allow support of Mac OS X within a virtual machine. The functionality is there already in Workstation but it's hidden away by default. El Capitan installs with no problems. It might work as an option for you if you're not overly dependant on the OS for native graphics. If you want Bluetooth/Wifi to work without any hassle, it's worth looking on eBay for native Mac components in USB or PCIE form (generally found by searching for hackintosh and the component)

Have you tried Horos?

This is great. I had a similar need for some work that I did and created a project that does something similar, albeit with less functionality ( https://github.com/spurin/gowebserver )

I took advantage of the cross os compilation and also provide prebuilt binaries for the various os's. Might be worthwhile doing.

I'll add a stub to the readme to see your project.