You're right, I don't imagine there are many teachers who make a move to the corporate world. Changing industries can be super difficult, but certainly not impossible! Your biggest hurdle will be getting past recruiters. They're trained to look for a very specific type of resume, and will likely take 10 seconds before rejecting yours. First, read through job descriptions of L&D Consultants to get an idea of the job requirements companies are looking for. If some items jump out at you that you know you could easily do, put them on your resume. In your cover letter, address a specific item (or 2 or 3) in the job description's list of requirements and talk about how you utilized those skills in the classroom, or on projects you've worked on, in dealing with administration, if you've had any committee work, volunteer work, etc.

Obviously adult learning has different theories and methods than teaching high school students, but quite frankly I think your job would be much harder. Companies are desperate for candidates who are innovative, smart, out-of-the-box thinkers and I would imagine keeping high school kids engaged takes a bit of creativity. Research adult learning theory and spell out the ways in which it aligns with the experience you already have.

Last, see if you can elicit the help of a search firm / headhunter. At the very least, they can provide you with some insight into the needs of companies in your area and will be able to coach you on interviewing and building your resume.

Oh! One more thing - there are certifications in L&D you can get, but I have NO idea which are worth it. I can only speak to the PHR / SPHR certifications, but those are generally used by HR Business Partners / Consultants and would not be quite what your looking for. Do a little digging to see if you can find one that looks reputable, and that will also be another community you can network with to get your foot in the door somewhere.