Id never thought about 3-D printing.. Nor do I know anyone local to me who offers it. If somebody here could 3-D print it, Id be up for that too. I am aware its going to be pricey.
To be honest, I dont want to use an Alpha Black reciever because I have a first-run 98C, with the first-generation "e-grip" kit intalled. The one that you have to hand file and fit into your receiver. It maxes out at 10BPS, but its a blast to use. It uses a gigantic pneumatic cyclinder to trip the sear. The Alpha Black frames simply wont accept the kit [without very extensive milling].
As "low" as the rate of fire it allows is, I like the older kit better because it is more robust, and has an external battery holder. No pulling apart the clamshells on a field picnic table to swap out my 9v if it dies.