The AMT is the only one I know of. I have an AMT and it shoots alright. The clips are a little pricey as is the ammo, now. I would suggest a .22lr or any of the auto pistol calibers from .32 up.
My mother is real small and not getting any younger. She couldn't handle a couple handguns I was trying with her. I ended up getting her a .410 coachgun with 3" shells. She had shot some trap and skeet in her younger days and warmed right up the smoothbore and uses it to get rid of the coons, possoms, rabbits, etc.. I even caught her buying shells at Wal-Mart one time!! <img src=icon_smile_big.gif border=0 align=middle>