Hmmmm. You say it's not a set of mortice chisels? Well, that rules out the those and the aforementioned dovetail, and as he already does paring and bench, then not likely to be any chisels. Unless it is the carving set...
What else requires fine metalworking tolerances as befits an advanced materials engineer? What about a pair of infill planes? Or on a smaller note, what about plane blades themselves?
Or perhaps you're throwing us a red herring, and it is in fact a set of chisels, but in an alloy he hasn't used for anyone else before?
He lists marking gauges etc on his custom tools section, but I dont know if a set has been produced before.....
Or maybe they are a set of 'tools', but not for the workshop? Kitchen knives, maybe?
A set of engineers' squares?
Ooooh, hold on, what about a set of screwdrivers? That's something that would be an exquisite use of Blue Spruce Tools.....
Ok, that's me out of ideas for the time being.....
Cheers,
Adam
P.S. Im still waiting for him to put his mortise gauge into production