A new Winchester Low Wall 5-barrel rifle set.
The action is modified with a Martini Cadet-style takedown screw... just snug in the barrel and screw in the takedown screw and everything's tight and where it needs to be.
I'd have two rimfire barrels, a .22 LR Match, and a .17 HMR. A separate 'guts' (everything that comes out when you remove the lever pin, breechblock, lever, extractor, etc.) for rimfire and centerfire.
I'd have three centerfire barrels, a .19/.357 Magnum, a 6mm/.357 Maximum, and a .357 Magnum.
The rimfire barrels and the .357 Magnum barrel would be threaded for suppressors. Barrel profile would be half-octagon.
How 'bout it, Santa? I've been REALLY good!