NUnit: any way to build test project to standalone exe?

I have NUnit test project in my solution. I'd like to be able to run its tests on a set of different environments using a network of virtual machines and then aggregate result XMLs from each machine to my server.

I guess I would need to install NUnit to all my VMs in order to do it that way. But maybe I can avoid it somehow? Hypotetically I can change my test assembly's output type from class library to console app and call all my test methods (those ones with right NUnit attributes) using reflection manually from Main method and write XML output myself.

So I'd like to know if there are any testing framework that can make it for me. Ideally I would like it to create standalone executable that I will be able to run on a bare installed system, with no need to install some additional testing software. This executable will run all its tests and generate some test result output (it better be NUnit-compatible, but it's fine if it's not, I can handle some post processing).

Any ideas how I can achieve this? Thanks in advance.