We had exactly the same problem earlier this year and couldn't source any DC fans which were 'traditional' in design. Instead we bought Hunter Outdoor Elements II which although AC still only use 3x the power of the DC fans (60W cf 15W under full load so not a lot different unless you have a house full on 24/7). These are good quality, have palm shaped (GRP) blades and come in rustic colors.
As a general warning - don't buy anything other than outdoor use types even for indoors as the sea blast on Bequia will wreak them. Especially avoid the Westinghouse units which break down or get salted up + the blades come apart in the humidity.
We got ours from Tec-Serv in Mustique who can source them from Europe and have regualr shipments right into Bequia. Not cheap though but worth it in the long run.