I believe all the ships today have wheelchair accesible cabins. You would have to talk to a travel agent and find one that is available for when you want to cruise. They are also noted in the ships layouts by going to their web-sites and looking at the deck plans. They don't have a lot, so it would be good to book that cruise early in order to get a cabin that works well for you.
By sure accident we were able to book a h/a cabin for Parrot Pop who uses a rollator. The shower alone made his life so much more pleasanter. Now I understand why these cabins are grabbed up by the handicapped and NON-HANDICAPPED. On another cruise line heard a well traveled passenger bragging how she always gets one because of her husbands knee..Her husband at no time had a cane, wheelchair or rollator and I personally saw him walking rapidly around the ship alone. It appears that these cabins "go first" when the bookings open.. they are the same price as a regular cabin,but not the same size nor do they have the same amenities. It really makes me angry that people who really need a handicapped cabin cannot get one in the next instance TEN MONTHS IN ADVANCE because they are all taken in their category.