I don't know what you need to improve on your mare, but Domino is very nice. http://www.andalusian-horses.com/ He sired a very fancy looking horse that I rode a few weeks ago, who happens to be a SUPERB hunter, with placings at AA shows.
My suggestion then is either of the stallions at Rancho Del Lago. Their stallions are multi national champions and have both consistently produced big moving, super trainable babies. Even when crossed to mares of other breeds they always pass good movement and good minds. (Magico has a multi national champion Spanish Norman [Percheron dam] daughter who is 16.3 and a great mover!)
I have ridden their boys and they are lovely. So lovely I bought a Saltador ORO colt from them!
Both are at least 16 hands, I think Saltador may be 16.1.
I met the stallion Fetichin, who is in Ohio, last year and was so impressed by his look and his temperament was fabulous. She has another Andy stallion as well, but I thought Fetichin and his offspring the clear standout.