I found out by chance a publisher that has "Gregg Speed Studies" in print! How can that be? The publisher is Kessinger Publishing Company, http://www.kessinger-publishing.com. According to their web site, they use "advanced technology to publish and preserve thousands of rare, scarce, and out-of-print books".
Now, if we could only twist their arm to have available other hard-to-find Gregg titles, I would be a happy camper ...