Assuming your toilets have a tank there are some wall-mount toilets but usually two-piece. The American Standard Glenwall is one of them. We are in a similar pickle, one tank broke and, of course, Kohler did not have replacements anymore. I want to get away from wall mount yet avoid re-plumbing (space problems). So I am looking at the American Standard Yorkville which sits on the floor but discharges to the back. However, the waste plumbing for that one must be at exactly 4" above the floor.
Be prepared for sticker shock. Whether wall mount or rear discharge these are usually well above $400 and special order.