Sounds like you're talking about cast bullet sizers, not dies. If not disregard the following.
I've purchased custom push through bullet sizers directly from Lee. Usually turnaround is about 2 weeks, could be longer right now.
Lee has stopped producing the old style push through for standard 7/8x14 press fitment. The type that had a catch bucket on top of the die.
They now have breech lock style sizes which have some pluses and minuses. It requires you to have either a breech lock style press already, or a press with 1 1/4" or 1 1/2" bushing to use their "update kit". The positive is once you buy the sizing die body, each additional size is only $20. Custom sizes can be made up to. 515" and
@AJC1 they have sizes you may be interested listed as custom overruns (458, 459 and 460) on their site right now.