There are some options out there, from landing page themes on sites like themeforest, to plugin systems like premise and Saas apps like Unbounce to whatever you would call Prosper202 to... well, there's a lot of stuff out there.

That said, twitter bootstrap has most of those elements, even down to the hero-unit already built in, so I guess it would qualify for that too.

I gave this as an introductory read to our junior web marketing team. it would be really nice to have a bootstrap landing page and I am surprised why Google does not provide such resources?