It's the high direct heat from the coals that chars, the metal bars that make the stripes, so stripes without flame - a grill [griddle] pan.

Pre-heat dogs & pan, then a minute or so each side to put the stripes on. Works for steaks too.
This seems to be dividing the field somewhat on up- vs down-votes.
Maybe this is more useful for the Brits, who tend to have a shoebox-sized live-flame charcoal BBQ about twice per summer [one of which will be ruined by the rain anyway] so we are used to grills that will turn anything put on early into pure charcoal in under three minutes, whilst anything put on half an hour later stays raw. For those too eager to get the food on it there's also that delightful smell of paraffin to add zest to the first round of charcoal-crisp burgers.
We also pre-cook our chicken portions in the oven, for fear of killing the guests by serving thighs burnt to a blackened crisp on the outside, whilst still being raw in the middle.
For the US with your football pitch-sized grills powered right from mains gas, with smokers, mesh lattices & assorted steel hot-plates at various heights - generally looking more like an office block under construction - this might be less useful. Or you already have one built-in, over in a far-flung corner of the structure out of easy reach, behind the half a cow currently slow-cooking…
;)
…plus, the Brits can take this indoors & put it on the stove when it rains - so long as they also remember to bring the buns in, and send one or two of the more water-resistant kids back out to fetch the beers too. Everybody can then have lovely looking hot dogs whilst gazing out of the window at another bank holiday ruined.
My comment on another answer would work too - get a George Foreman grill [They didn't have a hot dog recipe to borrow from, so here's some chicken] …

That would work for the Brits too, if they're expecting rain ;)
Examples, for those who have never visted both sides of the pond…
US barbecue


British barbecue
