I have my personal '72 sitting next to this one waiting for it's turn. Along with that I have a few non-Z Datsuns that need the same treatment. I really enjoy the build more so than having a car too nice to use sitting in the garage, so if someone else could enjoy it and enable me to fund the next one it's a win win situation in my eyes. For some reason I am a glutton for punishment.
The increased popularity of these cars has definitely made scoring a "barn find" example difficult and more costly. On the flip slide restored examples are fetching healthy numbers, so in a way it all evens out.
From what I have seen recently, a good restoration candidate can fetch $5,000-$15,000 depending on year, condition, rust, completeness, etc. Hard costs for parts and materials can vary greatly depending on the restoration direction - factory spec, resto-mod, track car., you name it. Labor will probably be the biggest factor in determining what kind of profit (if any) you can pull from one of these cars. Over the past 16 months we have racked up nearly 1500 hours to build this car. Being that combined we have 35+ years in professional auto body/paint and mechanical engineering, all the labor minus the engine machining was done in-house. I could imagine paying someone else to redo the interior, complete the body work, assembly the rolling shell, etc would quickly eat up any margins.