Hi Shaun,
I'm taking advantage of the feedback from those that have well worn the road before us, and the message was loud and clear,uncertainty of finish time, potential unknown issues, mechanic distractions to finishing, performance and reliability in the long term is based on the block you start with so it better be good, lack of warranty (Ross Hughes from Melbourne who represents the engine factory in Oz/fordcobraengines.com will have your own mechanic honour the 20,000klm warranty, Roush do 40,000 klm) , dyno'd set up prior to shipping, no final price confirmation, just too much upside for me but purchasing a crate.
On the other hand, there would absolutely be great pleasure in building your own and if you have the situation where this fits your interest, resources and approach I'm sure it would be really rewarding, I guess I just am not in a position to follow this path, but there are many more really good engines out there built the way your suggesting, than bought as a turnkey. From an originality sense, this is clearly superior too.
Different strokes for different folks and I'm just an impatient bugger and like concrete concepts!
Cheers Bee