Several months ago I picked up a 2S .458 set that has both a dish as well as flat face external punches for the CS and PF dies. It's meplat is .125". Haven't had time to try it out yet. I don't believe you'll ever see a BT or RBT set in this caliber. That design is basically reserved for sub-35 caliber slugs that are expected to perform equaly well thruout the range of 1200-2700 fps. Flat Base bullets tend to become slightly unstable at subsonic speeds at the end of their flight, so BTs are excellent for 600 yard shots. I don't think .458s are used with such ranges in mind. That's why most of them have flat bases and very round noses ( 1E or 3/4E), or flat noses ( meplat of .3 or .4): they are used for very short ranges to make really big holes. Spitzer bullets in this caliber are usually 2,3, or 4 S and are sort of hard to find, and are, I believe, only slightly more stable than the RNs, due to the velocities usually loaded (recoil can be brutal at 2200+ fps).
