You can quilt on almost any machine, but I got frustrated trying to quilt on a double size quilt in the regular sized area. I bought a machine with a larger area (harp) from needle to side.
My Janome 6500 came with an acrylic table to have a flat surface to move the quilt on. I don't need the table since my old cabinet has just enough room for the machine to fit inside and be lower to my level.
I agree to go to the dealer since you want more than your old machine offers. You will get great advice here too!