Desert Rose (Adenium obesum) can make for a very interesting container plant. It is highly prized in S. Florida for its large caudex trunk which develops with age. Interestingly, it will only develop a caudex when grown from seed, so it takes several years to mature. When grown from cuttings, the swollen base never develops. There is a wide array of flower colors on the market today through hybridization, and many growers are grafting these hybrid colors onto established root stocks.
Richard Lyons Nursery has a very pretty red and some pinwheel pink and white flowering varieties grown from seed, so the caudex will develop over time.