Ok so I have a customer who has ordered a retro coke machine cake. So I was thinking of making the cake 10 x10 and stacking the cakes on top of one another and putting fondant over the whole thing. Now where I think I am going to have a problem is the delivery of the cake, I am worried that it will fall...Any suggestions any info would be greatly appreciated.

Dowel it from the inside before you cover it with fondant and you should be fine. Post a pix when you're done, I can't wait to see it!

Personally - I've had a lot of experience with cakes falling! I would have a base of wood, then screw a 1/2: - 1" towel from the bottom in. This way you KNOW it isn't going anywhere.
I hate transporting cakes, wish they would just pick them up themselves!

What model of coke machine?

Is it a cooler, squaretop, rounded corner, early or later model?

I've refinish machines as a hobby this got my attention.

By the sounds of it you'll need a fork lift. LOL It's going to be huge.

I would attach the dowel to the board also. And make sure your base board is really big which will give it more stability. I made a 4 stack beer can and didn't have a big enough base and it kept tipping. Had to be very careful. For added strength you could add some extra dowels throughout the stack. Good luck ... looking forward to seeing it.