I agree that it is possible. The racks are roughly the same size as my FEC-100 and I could easily cook a whole comp on it. As Jaskew mentioned, the timing is important. I cook two butts and two briskets, 4 racks of ribs and 16 thighs. The butts and briskets cook overnight and are usually done by 9:00am and go into my Cambro to rest. The ribs go on at 8:00am and chicken at 9:30.
Now... having a second grill or smoker is handy, especially if you want to do the ribs or chicken at a different temp, but it's not necessary.