Tony, it sounds like you have tried most of the options. You could also have the one player who can play both F and D rotate through the F's and the D so the scoring line is broken up less oftern.
Having 5 D is a good option and when a D gets a penalty then you still have 2 sets of D and if a player is sick at least you have enough D or forwards.
Tom. I appreciate your thoughts. We tried the 5 D lineup and were not as successful. I'm not sure if that was due to playing with different defensive partners or the fact that we had an off night versus a stronger team.
We played a tournament over Thanksgiving where one of our top forwards was absent. I placed my floater player from our crazy rotation, another top player, in his position at center and realized he plays much more effectively playing one position. Our entire team seemed to play much better having 2 sets of forward and defensive lines.
I now have to figure out how to integrate the absent center. I'm leaning towards trying the 5 D setup since it gives more flexibility with penalties, absent players etc.