I am having the same problem in quilting a t-shirt quilt. Have you decided how to do this? I too don't want to quilt over the logos and personal pictures I incorporated into the top.
Thanks w7sue. I decided to just add the sashing to one side of the blocks to make them even. I have the top done and have it make into the sandwich. I will try and add a photo.
Now my problem is how to quilt it. I don't want to stipple over the logos. And I am afraid because of the size of some of the them it will be too big not to quilt it someplace.
I've never done this kind of thing before, but could you sash each logo with different sizes in order to make them all the same size? Does this even make sense? If you have a six inch logo and want it to become a twelve inch block, then you could add several borders until the desired size is reached. If you start out with an eight inch logo, you would use less borders around it to make it into a twelve inch block.
Good luck, would love to see a picture when it is finished.