One of the most important factors on a PPC landing page is message match. You must ensure that your ads message is cleearly repeated on your landing page.
From an SEO perspective, this means making sure that your page title and h1/h2 tags align with the messaeg you are putting across in your ad copy.
Something I have been working on is having my ad headline as the H1 on my landing page, and my ad body as a H2 on my landing page. Then having the title of my page be something like "%Ad heading% | My Site".
It is definitely worth trying this out as part of your A/B testing. some of my landing pages using this technique are getting conversions around the 8% mark.
It is also worth trying to get your message match in your URL title as well. If you are ad heading was "Top 10 SEO Tactics" for example, why not have your landing page URL be something like http://www.mysite.com/top-10-seo-tactics.
On another note, I don't think you would need to create 100 different pages for 100 keywords. you could have just one page that does some text replacement to ensure you keep your message match. I usually create a landing page and then replace some tags within the page depending on what ad users come from. This is pretty simple to do in .net/php and will save you recoding up lots of pages.