<creepy voice>
If you have the money, they will be made.
</creepy voice>
Sarcasm aside, it's true.
IPP
They can custom make any pistons through their OEM's or in house for pretty much any project.
Generally they'll ask for the dimensions you need them in, if they don't have them on hand.
This is not to say that anything will come cheaply though.
I know Tony has dome quite a bit of work, among it I do believe he dropped some CR to bump up the boost, though I can't confirm it. Perhaps he'll drop in and let you know.