I know zero about this guy, but he makes some pretty nice automotive electronics problem solver devices for reasonable prices. He has a 100% positive feedback and has host of positive reviews.
I'd be willing to bet he might be your man to make such a starter switch to your specification. It may be another item he can sell on E Bay too if it works out.
Maybe something to ponder getting in touch with him:
https://www.ebay.com/c/2283353303