Those 0.5’s are on my list.
I need some of this in my life
Nice set, Allen! @DarkwingDuck
Great selection, I see many special items over there. While I prefer the “bare” versions, namely without the sanded grip area, I reckon it is a distinctive feature of the model, and I am afraid some versions do not come at all without the sanded zone. The perpetual calendar Fixpencil 25 is a true gem, in impeccable conditions: chapeau!
I still hope to find one of those round Fixpencils leadholders one day (I spotted a listing for a pen, but no pencil so far).
Round? Which are you referring to? 44?
No, the Fixpencil 44 “Museum” is the other round one (and the newest). I mean the old Fixpencil 24, available in both BP and clutch pencil form — or maybe the BP was just a BP refill stuck inside the clutches of a leadholder.
There should also be a Fixpencil 26 (similar to the perpetual calendar one, just with a rotating lead hardness indicator where the perpetual calendar is located on the 25), a number 29 which seems to have a split mouth for securing 1.18 lead, the Fixpencil 1 (or “I”), also a clutch pencil but for 1.18 lead, and many many more…
The Caran d’Ache Fixpencil family is like the Snoopy clan from Peanuts or the Goofy clan from Disney: as soon as you think you have seen them all, here it pops out another one… 
That’s awesome!