Q: Can we create one off landing pages specific to an industry and use SEO to drive traffic, with the landing page as a static page with no links to our main website?
A: Yes you can certainly use SEO to drive traffic to a landing page such as the one you described. The process will be the same as it would be for a page on your website, with one exception. If the landing page is on a separate domain then it will not benefit from the previous SEO done on the main site. So you will be in effect starting from scratch.