For those of you who only insist on using payware aircraft, Alphasim is currently creating a Britten-Norman BN-2 Islander for FSX, and possibly FS9. Screenshots have not been released yet.

For those of you that are fine with quality freeware, and use FS2002, or FS2004, (not sure if it works in FSX) a very nice set of various Britten-Norman aircraft are available here:
http://www.m-r-software.de/

I would highly recommend you try out the freeware Islanders, they are quite good in my opinion!