Looking for a tube planisher

we make alot of tubular and conical sheet metal parts. 24 up to 12 gage. 3 inches on up in diameter. parts are rolled then spot welded then the weld is worked on a horn with hammers to even out the curve and tighten up the lap. this is time consuming and noisy. I previously looked for a light duty plannisher but only found english wheel types. I can build this but would rather buy it, ideally a arm with a bellied steel roller that would work down to 3 inches ID and a top roller that would be air loaded. this has to work with tube, ie in and out verses perpendicularly. if i have to design and build something i would probably make 2 different versions one for light work and one for heavier work.
does anyone know of such a bird?
thanks