For kicks, I do have a 9.3x64 based on the 30-06 case. A 366-06 if you want. Pre WWI vintage, ammo not made since 1930 or so. But people did try.
I used to love being able to hit hard at 1000 yards. As I get older I find hitting a mini ram at 200 yards with the 22 oddly more satisfying.