Hi Lee,
I'd approach it like this (it's also how we do it at Unbounce).
To get it ranking in the SERPs (and be successful in general), I'd do:
- Write a blog post as you described. This would be the launch of the ebook. It should essentially be a preview of the ebook, either a chapter or some ket highlights turned into an original blog post.
- Have all of the ebooks for this client live on a subdomain such as get.clientsite.com/ebook1/ get.clientsite.com/ebook2/
- Make sure you have an XML sitemap listing all of the pages on that subdomain
- Create a resources page on the client's website to provide another link into the ebook page
- Allow two methods of digital currency in exchange for the ebook (pay with an email or pay with a tweet) - see this ebook landing page as an example - http://get.unbounce.com/conversion-centered-design-guide/. The tweet version allows the page to have a viral loop to maintain the momentum of the page.
- Have the client email their list to drive more people to it. The more people see it the more will link into the page.
- Have social share buttons on the confirmation page to get more exposure to the ebook landing page.
- Do some outreach to friends, colleagues, blogs etc. that might be able to add a link to the ebook.
- Do a guest post with another portion of the ebook expanded into an original piece.
- Do a Slideshare presentation of the ebook. This will get you listed in the SERPs immediately. Make sure you have a CTA at the end of the presentation linking to the ebook landing page.
That's a few things off the top of my head 
Hope it helps, cheers.
Oli Gardner
