I think you have stumbled into the famous glocktalk ******ry. if you had posted in the 10 ring
you would have had a much more positive response. most of those folks are knowledgable about such things but dont read the general forums due to just the response you got.
So, yes I have heard of the 224 BOZ. lots of fun dont know much about it/
yes I too would LOVE a .401 sabot, but have never seen anyone who makes one.
I'll bet that we could get someone to do it with enough demand but plastic molds are expensive (like $5k+) so economics of scale might be questionable.
Running some numbers thru Quickload, the immediate problem I see with the sabot is that due to the length of the bullet seating depth is so deep that it restricts powder, and even with fast powders, a 55-75gr projectile will still only reach about 1700fps. This kind of defeats the whole point of the exercise as some guys are getting 1600+ with 135gr Noslers already.
Another note. They make mounts for red dots that will slide into the rear dovetail on a fiveseven. also you could call Dave at Bowie Tactical to see if he can mill the slide on one for a red dot.
your dream pistol is here, you just need the cash to do it!!
Good luck and welcome to the forums. check out the 10 ring and it's sister the 10 reloading forum.