Is a full sheet cake 14x22? And if so, where can i get a pan that large? Or would it be 2 halves pieced together? My grandmother in law knows someone that would like to buy a sheet cake from me in May, but I have to buy some pans and I'm not quite sure what size to get.

I think it is really what your want your full sheet cake size to be. My full sheet cake is a 12 x 18 X 4, my half is a 10 x 15 X 4, and my 1/4 is a 9 x 13 X4. Some people make their full to bigger sheet pans and put them together...
It's all a matter of your personal preference!

I consider a full sheet to be 15 by 22. I don't have tons of storage space for big pans, so I just put together two 11X15's. The Eagle Scout cake in my pics is this size. It seems to work and is helpful when you want to do the popular vanilla/chocolate combo (1/2 the cake vanilla, the other 1/2 choc).

Sheet cake sizes:

http://forum.cakecentral.com/cake-decorating-ftopict-81011.html

1/4, 1/3 and 1/2 sheet cake pan sizes:

http://www.bakingshop.com/sugarcraft/cakepansoblong.htm

HTH

I believe a full cake is 2 - 12x18 side by side this will feed you about 96 people. A half would be one 12x18 feeds 48, and a quarter is 9x13 feed 12-15 people.

Hope this helps.

I asked this same question a while back and someone suggested calling the bakeries local to my area and see what sizes they use. I did, and there was a big difference with them as well, so I use these sizes which were suggested in the other thread:

1/4 sheet - 9 x 13
1/2 sheet - 11 x 15
3/4 sheet - 12 x 18
Full sheet - 2 11 x 15 put together
Texas Sheet - 2 12 x 18's put together

HTH

Maybe...But it is how I find it to be the easiest for me...Thanks for taking time to think about that!