Firstly, thanks very much for the information Brian, it's certainly very useful. Those Nick Sonder video's are really very good and he's produced them very well. He should consider doing a series, he could even charge a little bit for them, i'm sure there would be plenty of people who would be interested.
In answer to your question, i'm a an Aerospace/Mechanical Engineer by trade, but looking to design and build my own home on a plot I have. My intention is to do a lot of the design work to get to know my plot and understand the comprimises that I might have to make a long the way, based on practicality, cost, etc. Ultimately i'd like to pass something on to an architect as a package and have them take my design and assess it, make any alterations for regulations or code, plus change anything that might not be suitable.
I will send you a PM as you've kindly offered, as this is something i'd like to look into. I've currewntly got the free version of Sketchup, but am keen to upgrade to the full version to give me 2D capability, but would like to evolve a basic concept design first. This kind of takes me to my original question as to if any house model exists, like a Sonders model that is available to see and play around with the model setup?