I can't imagine dropping the tank is much easier than dropping the subframe, and even then there isn't much room to work as already discussed above. I haven't done the engine out service myself yet, but will within the next couple of months. Great opportunity to fix lots of little things that likely need done and can't easily be done if shortcutted. I also remember the F355 with the fuel cell in the trunk to allow for permanent access to the front of the motor. It seemed very silly.
Remember the guy here on the forum who got fed up with it and moved the whole tank to the front of the car to be able to service the engine?
That's not a bad idea, probably helps weight bias as well. I am in no danger of doing it and there is only so much you can do through the tank access area, still need to remove it I suspect, but still.