I also love the mock-up, it certainly shows a lot of potential.
Scale is the problem factor I find in many of my builds. When trying to keep something fairly small, you run into all kinds of problems of fit, function and finish. Generally the larger scale you build to, the easier that build will be to accomplish, but then material costs / weight / handling / storage issues start becoming major factors as well.
Somewhere there is the perfect compromise on what scale to use for any given build, but for us mere humans, perfection in anything is most always unachievable!