How to keep a meatball round?
I saw a recommendation on 30 Minute Meals to place each one in a muffin tin (they were sized so they stuck out the top), and then bake them.  You'd have to find the right sized tray for your size of meatballs, though.

I'm guessing you'd also want a large tray underneath, though, or you risk dripping grease inside the oven.

... you could probably also just put 'em on a sheet tray and bake 'em, and you'd only get one flat side, rather than from each time you turned them in the pan.