You can use a quilt as you go method and embroider separate blocks or sections then join. You can also purchase an 'endless' hoop, where you can easily advance the fabric. Designs are digitized specifically for this hoop to make the individual hoopings seamless. I have done a runner for my dining room table this way. My table is 17 feet long (seats 20) and the runner came out great.
It is a learned skill, however. I agree with everyone who said do a practice piece first!