This app was mentioned in 2 comments, with an average of 1.50 upvotes
Damn, I was just about to suggest Kustom, too.
I actually had Car Home Ultra for a while and I liked it. It has been a few years since I used it but it was nice because you could customize certain pages for driving and the buttons were huge, like you wanted.
I hope that helps. Again, I haven't used it in a few years.