Always the elephant in the room and even more so with Project X... repair parts. When I lived in Huntington Beach during the 1970's, a town nearby was Costa Mesa. In early 1940 it was home to many Japanese Truck Farms.
The order to intern the Japanese Americans literally wiped out all that piece of the truck farming. Many owned the land, and it was simply confiscated. The Costa Mesa Japanese Americans ended up in the Poston, Arizona internment camps (3 of them). The history of the camps is an interesting read and documented in a You Tube Video
Post war Costa Mesa diversified into the electronics businesses supporting aerospace and defense and that gave rise to the potential of electronic surplus. One such store is Marvac Electronics who have a store front and sell on eBay inclusive of new and surplus parts. Believe it or not I actually found some of the obsolete semiconductors used in Project X at Marvac (about 90 miles from my QTH).
Oldie NPN (Yes, NPN) Germanium Transistor
I made some visits to Marvac when I lived close by and recall the prices seemed a bit higher than what I could find at the TRW monthly swap meet near LAX. But today, when you need something, you get it and actually their price was the lowest on eBay. I bought it on Sunday and got a note at 9AM on Monday, that it was shipped. I will have it on Wednesday. Check out Marvac as a source for some of those old parts that appear unobtanium.
Some portions of the project will and did involve hand making parts and one of the control knobs was missing the aluminum insert. KE9PQ and K3ICH sell these inserts, and I purchased some for Drake and Hallicrafters main tuning knobs. But their inserts would not even come close to the small sized oddball knobs used on the Project X radio. I found that the insert size was just slightly bigger than some old disc ceramic capacitors kicking around the shack. I also had a stock of really thin hobby aluminum. Trace the disc on to the aluminum as the outer trace lines were just about the right size. Out with the jeweler's files and we have an insert.
Not perfect but good enough for government work!
Them that know can make it go.
73's
Pete N6QW