Hoya carnosa compacta is pretty slow growing, looks great in a hanging basket and can stay in the same pot for years. My own is still in the same pot I put it in when I got it about 4 years ago and I have no plans to repot any time soon!
Of course mine was a full 6-inch pot when I got it; those arms are about two feet in length now. Smaller pots and single cuttings are available. But keep in mind that no plant is going to stay 'small' forever unless it's constantly pruned back or divided up. They GROW. It's what they do.
As for where to buy them, it's probably easiest to find them online. Local nurseries and garden centers seem to get them only once or twice a year.