Having built a desktop simulator myself, all I can say is "Hang in there" - the results will be well worth the effort! My current simpit took about 6 years to design and build, and it went through at least five design changes along the way! I started off designing a full cockpit like yours and TowerGuys sims, and then devolved it to something more modest. It was originally going to be a fully enclosed C172 sim, but I quickly realised that I wanted to be able to fly anything from Cessna's to 747's and everything in between. I also lacked the necessary funds and space for the project - so I settled on building something that would fit on a normal computer desk, but would also provide the immersion and realism required for it to be more than a simple 'toy'. The result of which you can see below.
The cardboard mockup stage is a very necessary part of the design process and will save you $$$ in the long run as you don't have to waste expensive materials on idea's that don't work!! Stick with it, I'm sure I speak for a lot of people when I say I'll watch this and TowerGuys projects with interest.
Best of luck!!
Mat
Early on in the design - mocking up the instrument panel with cardboard
The end result - a desktop simulator capable of controlling ANY FS aircraft! This being the PMDG 737 with RealityXP gauges on the panel, and GoFlight and Elite hardware
Nothing is better than flipping switches and having your simulator come to life!! This shows some of the GoFlight hardware and an electrical panel of my own making
cardboard , the 
Nice one yeah what you said Ian ,bit of chicken wire and fibre glass and you really do have a MD500 AWESOME dude love the inspiration you have ,hope it all pans out the way you want it too ,keep it up man ,,side note the misses and i had a good chuckle ,,but mean as blue print and effort 
