I wonder if Cappuccino has considered using make. make is maintained. make works on Windows. make is unglamorous but it works and it has worked for decades.
And yes, we tried Nailgun (http://www.martiansoftware.com/nailgun/) but I don't recall why that didn't work out.
Perhaps there were better solutions, just pointing out it wasn't completely NIH syndrome.
* nmake, bsdmake, and gnumake are all slightly incompatible with each other if you want to do something smart.