Mixing Cotton and Jersey in a quilt?

I am new to quilting. I am planning on making a T-shirt quilt for my son for Christmas and was wondering if it is wise to mix the T-shirt fabric with regular cotton. My plan was to have a big T-shirt-patchwork in the center and suround it with cotton sashing (about 6 inches wide).
Has anybody tried this or experience with mixing types of fabric?

I've seen patterns for quilts where they cut t-shirts for the center of blocks. These patterns call for you to lightly interface the t-shirt knit before sewing it into the quilt.
Since your quilt will be almost all knit, I'm not sure if I would interface all of it. You may have some trouble keeping things from stretching while attaching the sashing, but I think you could do it. Just use alot of pins and go slow.