I know it's OT, but why would you want a custom crank shaft made?
I would assume that this question is 3S related, and I dont think I've ever heard of anyone running a custom crank, even the guys making big HP with turbos, or even the 8700rpm 240hp ATW screamer 3S engine of CelicaRA45.
1988 KE70 Wagon - Slowly rusting 1990 NA6 MX-5 - because reasons 2018 Ranger - Because workcar 1997 FD3S RX-7 Type R - all brap, all the time OMG so shiny!