Hi there,
The theme is not wordpress, but I can develop a site like this for you. I have a super duper mega menu plugin that will do just what you require on the menu.
The rest of the site will be 100% responsive and will look great!!
I can develop the whole thing for around $250, instead of hourly if you prefer. That way we cap it off and you know exactly what you're spending.
Let me know if you're interested in this approach.
Best regards,
Emily