I bought an mbx11 rollers. I like it. You tend to sit down in a dip of the frame which keeps it from wheeling excessively.
Motovox doesn't have any 10 or 11 rollers. I was in sears last week and they had 8 mbx10's in the box. Pricey at $399.
BJ's is selling the Coleman mini.
Tractor supply still stocks the warrior or whatever the big bike is called now.
Search craigs list daily. You have to search for minibike, mini bike, baja, motovox, doodlebug, doodle bug, because their search sucks. Doodles and motovox's come up all the time here for $200. or less.