Though it may be after your trip, I have found from a couple visits to Bermuda that it is nearly impossible to rent a sailboat anywhere on the islands.
The ony lead I recall was a shop in Somerset at the dockyards, but that was many years ago. About the only watercraft available are kayaks, whalers and jetskis.
Now if you can hook up with a local, they have some pretty awesome sailboats, including a couple foiling boats. In fact, Bermuda is the only place I'm aware of where its legal to finish a race with less crew than you started with.
'88 H18SE Arís