So, I haven't been doing cakes for very long and I've decided to make my own cake for graduation. I've picked a design that looks pretty simple, but I'm not sure how to construct it. Here's a link to the picture:
http://www.kathyskakesllc.com/graduationcake005.html

I'm not decorating mine like that, but that's the shape that I'm using.
For the smallest tier, I'm thinking I should use 1 cake mix and make 2 8x8 cakes to layer on top of each other. For each of the two middle-sized tiers, I'm planning on using 3 8x8 cakes (each made from 1/2 a cake mix). Then, for the biggest tier, I'm planning on 4 8x8 cakes.

First of all, does that sound reasonable? (I'm planning to serve somewhere between 200-300 people, and I don't mind if I have leftovers)

Second of all, how do I go about layering these? The smallest tier will be fine as it is; it can be cut and served just like that. But what about the tiers that are 3 and 4 layers tall? Do I separate them in the middle with a cardboard cake board, so that they can be cut into regular sized pieces? Like, the big tier with 4 layers would be way too tall to just cut and serve like that.

I have a 12 x 15 pan.. you could do 3 6 inch sqs to do 3 of the cakes... and then a 9 inch sq.

first of all for the 3rd layer.. that you are worried about.. use a cake board.. and make sure you dowell or you might have sinkage...

Let me think more about the design.. (Im not to smart in the mornings LOL)

Great design though, very different!

Ok how about this... Bake 2 14" square cakes and out of 1 cut an 8" square. and place the square on top of the 2 14" much more structurally sound. does that make sense?

OOPs..

ok bottom layer could be a 14 x 14 square..

then 7 x 7 squares for the smaller ones!!! Still thinking...

ok scratch the 14" that would only be 98 servings.. plus measurments wouldnt work out. its early......
16" square would work... bake 2 layers out of the top layer cut a 8" square. and stack the cut 8" onthe top corner of the 2 layer..
how about that! however that would only serve 128 per wilton servings chart.. you could make a few side cakes...

hey wgoat5 I think we are on the same tract... great minds think alike! hehehe

The reason I say 16" cakes is it will be more solid cake... the more pieces you have the harder it is to keep those cakes together structurally.. you want it to be as stable as possible.. a lot of hard work goes into these cakes and you don't want any disasters.. So try to have as much solid cake as you can.. if you have to make cuts.. dont worry just freeze for aprox 1/2-1 hrs & make your cuts and then crumb coat, let it crust then frost as usual. I hope this helps... any questions just ask...

There is no way to get that many servings from that design only. You will have to make sheets extra. You could put the 16" sq on top of a 24x18 sheet (made up of two 12x18 sheets set side by side) to get enough serving out of one design. OR just have the sheets seperate.
It definately is made from two layers of 16x16x2. As has been said, from one of those layers you cut a smaller sq and place it on top of the two.

Thank you everyone!
I definitely see now that the cake in the picture was made from 2 16x16 cakes. That's what I'm going to do. I'll just cut an 8" square out of the top cake and add it to the top of the opposite corner. I realize now that it won't be as big as I was envisioning, but I also realized that my estimate for people was too high. I've been working on my invitations and now I'm thinking it'll be 200 people maximum. I haven't decided yet whether or not I will make some other cakes on the side.

My question now is how to bake my 2 16x16 cakes. How many cake mixes will I need for each 16x16 cake? Three maybe? Then, how do I get that to bake evenly? Will putting a flower nail in the middle be enough? And would it be structurally strong enough if I only dowel the tallest tier?

One last question- my plan is to but a cake board between the 2nd and 3rd layers on that largest tier, so that my pieces won't be ridiculously tall. How do you put a cake board between them so that the pieces from the 1st and 2nd layer won't look ugly?

That cake was done with two 14" square cakes and doesn't need any support for the top layer. Have you baked with a 16" square pan before? They won't fit in all ovens.

So do you mean that I don't need to use any dowel rods at all?
I've never baked with a 16 inch pan before, but I just measured the inside of my oven and it looks like it will fit (it's close, but I think it'll work).

Also, could someone please explain specifically how to use cake boards between the layers so that they will still look nice when the bottom layers are served?

You don't need any cake boards or supports in the cake at all. Not even when using 16" square pans. I've done several with 14 and 16 inch pans and none had support or extra boards in them. Some traveled about 30 miles with no problems. Just the base board which was 1/2" sanded plywood.

But if I don't separate the layers at all, how will I cut the pieces from that back corner without them being ridiculously tall?

You can slice the tallest layer and then cut each slice in half or you can just cut through the top layer first and remove those slices, then cut the second layer, then the third. If you're worried about the amount of frosting on each slice you can always fill a disposable bag with icing and let anyone who wants more add their own. Some people like cake with little or no frosting though. Especially at graduation time when they may be attending multiple parties.

Thank you all so much!!

What can I put this cake on? I mean... Wilton doesn't even make a cake board that big. Do most people just find a cardboard box and cut it up or what?

Head to your nearest Lowe's or Home Depot and have the wood cutting guy cut you a piece of masonite into cake boards. I just did this. I went to Lowes, got a 4x8 foot piece of masonite and had them cut it into various sizes. I think I got about 15 large cake boards for only
$10.96!!! They didn't charge to cut them for me! Looking like a pathetic lump on womenhood to the big heeman cutting the wood - I had that guy cutting ridiculous sizes for me!! LOL!!!

Thanks! I'll probably do that soon.. but for now, I just found a giant piece of sturdy foam board laying around the house. It'll work this time.