I agree and think you should definitely try for it. You have (at least) 3 years of a great base built up so even though you might have "slacked" on your training this year, I'm sure you can pull from the base you've acquired over the past several years. If this was your first IM, I think I'd be scared for you, but since it's your third (right?) your body knows what to expect, knows how the distances feel, and I think at this point it might be mind over body anyway. Good luck with the rest of your training - just don't kill yourself 2 weeks out from the race b/c you're trying to catch up.
(This coming from a 2007 FL IMer who's taking this year off to rest. Congrats to you for keeping up the spirit year after year!)

Let us know how it's going and if you need more support. If I lived near you, I'd come out and ride those 100 miles with you! Sometimes that's all it takes - just someone else to give you a little push when your mind/body is trying to fight back.