Let me introduce you to the needle and thread. People have been making quilts for a lot longer than this long-arm sewing machine you speak of. I mean, I guess my grandmother's arms were long, and she could reach all the way to the other side of the table she quilted from. Don't think she'd take too kindly to being referred to as the sewing machine though.

T-shirts already have a front and back. You just need some long running stitches to join two shirts together. Shove them with the amount of batting you want, and then another running stitch to seal them up.