I've got a couple of car cakes coming up next month. Using coloured icing or even painting silver on cakes seems to give a reasonable effect when it comes to the lights but i'm looking for something beyond that!
I was inspired by the Skoda advert when they made a life size car out of cake! for their lights they used big blocks of jelly! i wonder if there is anything that i could use to give a translucent glass-like effect on my cakes? has anyone got any ideas...it doesn't matter how wacky they are!
Using Isomalt Sugar and a small gem mold may work. I've never tried it, but that response popped in my head once I read your question. Clear gelatin circles may work as well. You could make a clear gelatin sheet and cut the size circle needed for your headlights. I've never tried this either. Just another light bulb idea.
I don't know how big your cakes will be but maybe go with real lights. These are called LED body jewelry here in the states. They are very small, about 1/2 inch all around. I used some in lanterns of a Tangled cake I made. Be sure to get the ones that don't flash
http://blinkee.com/product.php?id=White Steady Clear Plastic
I know there are other led options that are sold here in the wedding sections of some of our craft supply stores.
(Here were my Tangled lanterns. http://cakecentral.com/gallery/2019191/2019192 )