The carbine pictured at the beginning of this post is a P-ROD.
I own one, in a different custom stock and enjoy shooting it very much.
To make a bullpup you need the barrel, action and trigger group from a marauder rifle, a bullpup conversion stock and a Gen 2 bullpup trigger group conversion kit.
The marauder action and trigger group will be mounted at the butt end of the stock and the trigger group linked to the actual trigger mounted forward in the stock.
Enjoy!
The trigger pull is sloppy and your cheek rest is just above the bolt and mag. You will punch yourself in the mouth trying to chamber a second round with the gun shouldered.