I just completed a carbine project with my .45-70 Handi that I had rescued from a pawn shop. I found an adult-size straight-grip stock from GunParts for about 20 bucks, unfinished. I took the forend off, stripped it of its finish, and cut off that tacky little Schnabel tip (don't get me wrong, I like a Schnabel on a fine stock, never liked it on NEF's). I finished the stocks with a walnut stain and Birchwood Casey stock finish. A Pachmayer recoil pad completed the project. I left the factory sights on for now, but may go with a Williams peep sight later. The factory barrel is 22 inches, but the finished rifle is only a tad over 36 inches long and balances like a dream, just ahead of the trigger guard. If it were any shorter, it would be butt-heavy.
I picked up a NEF catalog at a gun shop last week, and they are selling a straight-grip carbine now in .45 Colt. It's a dead ringer for my .45-70, except for a curved buttplate and the Schnabel forend.