The "A-Team" did Career regs years ago but no longer, best link I could find for them:
"If" you are working on a Career (and you might try the yellow forum) you might try Anthony Storey in Indiana, I heard he can make one.
If you have a Discovery try here:
If you have a Marauder/Bam/AA/other try:
they are not listed on his site but he is the supplier so just send him an email. A useful link to installing a Marauder reg:
Best of luck,