As we speak I am using a domestic Singer to machine quilt a slightly larger than twin size. It is the largest project I have attempted. (I'm still a newbie) I had never changed the foot on my machine until a few weeks ago - finally got the book out, read it and changed feet and cleaned the machine. It was much easier than I thought it would be.
As for the quilting on small machine - it is tough bit I'm getting it accomplished. The clamps to keep it rolled up went by the wayside as the fabric ends up all crazy directions and shapes. I'm doing a basic straight stitch but having to turn the quilt often. It's not what I'd call "fun" but the more I do it the better I become and I've learned little tricks to make it somewhat easier. I definately will not attempt anything larger because this (quilt making) is suppose to for relaxation and enjoyment!! Might learn to quilt-as-you-go or just do small projects.