Are you limiting it to a "new" firearm currently in production? If so, the Rossi would be at the top of my list as well although I much prefer over/under gun combos.
The Remington International o/u 410/22 isn't bad... if you can find one.
I've heard lots of negative things about the M6 Scout in terms of accuracy.
If you would consider a used gun, you can't go wrong with the Savage Mod 24 o/u in 410/22LR... again if you can find one that is. Don't have to switch barrels, they don't weigh much so you can carry them all day.