In the book Pragmatic Programmer, Andrew Hunt and David Thomas say that 'checkout-build-test-deploy' should be a single command.(Chapter : Pragmatic Projects). You wrote..
I even have a potential investor lined up and plan to show them a beta version in the next few weeks
Then, I am sure your team is going to grow.. It is even more important to have automatic test-deploy abilities done.
The large XML (script) you saw, is typically a one time job. Most of the time, the same scripts can be uses across many projects.
It is not clear how large is the project. If your integrated tests/acceptance tests takes large CPU/memory you may consider using another machine as your test server. You could also deploy host of tools to analyse the source code/byte code.