Reinvention of a good wheel is generally not a good idea. I have installed
on several systems without a hitch (*nix and M$ systems). Having to install outside modules, really does not make the system less portable (unless the modules will not install on various systems, but as I have said at least one very good templating system does). Yeah there's a little more over head to getting the system installed, but I would rather take more time in the front end than not have a product or even worse have a poorly functioning product.
So to make a long answer short: I would recommend reevaluating the specification of no outside modules.