I always just built cushion walls around mine at that age. Then, you tie a non-chaffing rope to their ankle. You just follow the rope to their location, or if you don't feel like getting up when they scoot away you just reel 'em in. Make sure their head doesn't catch the door frame on their return drag if they're in another room though, they hate that shit.
My son has a corrective helmet on (yes, it's camo) because he had a flat spot that needed fixing. It's super padded so he uses it like a battering ram against our faces when he doesn't get what he wants. Gonna be in for a rude awakening when he gets it off in a few weeks and tries the headbutt trick again. Although I like your leash idea for my wife.
My daughter's method of throwing a tantrum as a toddler was head-butting the sheetrock. Not battering-ram style, but she would walk up, line-up and throw down some real kung-fu shit. She fucking DENTED it twice.