Ok, for our local campaign, we have a house rule allowing any basic weapon to be "combined" with any other weapon. Pistols may be combined with each other as well, but both weapons must start with the pistol trait. Ie grenade launcher/bolter is possible, but meltagun/grenade launcher is not. Plasma weapons so combined lose their high power mode for fluff reasons and balance. The combi weapon is considered the most restrictive category for wielding purposes, and adds both weapon costs by default. The combi trait and ammo check rule applies to both sides of the new weapon. While autogun/grenade launcher and bolter/grenade launcher are popular, Plasma/shotgun is also a thing for one goliath gang. Does anyone here see any excessively "beardy" combi weapons that need shut down?