Those ignotors are piezo. Very simple and cheap, the only expensive part may be to get a unit that fits the speicifc grill. As some guy siad, those gas ignitors are cheap, ad are piezo cigarette lighters.
If you want another solution, a cheap disposable camera with a flash, ready made. Use the centre 'trigger' connection from the centre of the Xenon flash tube. It's about 4-6kv very low current just be careful not to let the two wires from the main cap touch, or discharge through anything, its pretty potent, in fact, you could probably take that out, and just use the flash trigger circuit
my two cents,
Blueteeth