I don't know much about air travel between them, but how about Guadelupe? Looks like there are a couple of connections that get you to Guadelupe from SXM. Someone here was asking about the DR also, I think, and I think that is fairly easy. The DR is definitely more tropical, but it's primarily an a/i destination. Not sure whether the reason why you wanted to avoid Jamaica was because it's mostly a/i, or because you've been there before?