I thank all of you for your thoughts.
I have seen a 3 level high cage in person, a friend owns one. The way I see it is that Altair and Ezio have been in the Feisty Ferret the entire time I've owned them, and Zipper has been in the cage he has. Zipper will get a huge upgrade going to the FF, and I want to give Altair and Ezio a huge upgrade as well. The normal 2 story FN just isn't my idea of a great upgrade. I have thought about it being harder to reach them, and therefore possibly putting the cut out part between the top and middle cage.
SO to go over points made:
-They could fall
--True, but I have great practice putting in lots of big shelves, and smaller ledges for my guys. I've also already ordered hammocks that would make it so they'd have to weave down anyway. Their current cage is set up, as stated prior, that you can't even see the floor because I have so much over lapping.
-It's tall, need a ladder to clean
--Got one, and it doesn't bother me any. I've also talked to my fiance and he's fine with it.
-Not putting the storage on + bar spacing
--I had wondered if you could skip that or not, figured I would find out when we got it. As for bar spacing, I think the FF is about the same as the FN. We make do very well, not an issue.
I hope that answers that well enough, that I've actually thought about this and do have some idea on what to do. Feel free to bring up other points.