Ironman Florida is certainly an alternative. However I ran Taunton in 1997 when I didn't get in at London. It is a 2 loop race (combined with a half marathon) and you would describe the course as "undulating". The vast majority of runners do the half; so the second loop can be a fairly lonely affair (anyone who has run the Robin Hood marathon will know what I mean). It is nevertheless a well organised, friendly race but you will need to add 10 - 15 minutes to your target FLM time, perhaps more if you are a slower runner.