I have made over 25 bowls and you do not require this expansive tool, you can get the ball sander at Lee Valley Tools: http://www.leevalley.com/en/wood/page.aspx?p=56679&cat=1,42500,42504
I also use this sander http://www.leevalley.com/en/wood/page.aspx?p=49254&cat=1,42500
and I also have this one which I used to sand the bowls after initial cutting; http://www.leevalley.com/en/wood/page.aspx?p=45190&cat=1,290,42500,42504,45190
Also I order the small ball sanding tool from King Arthur tool : http://www.katools.com/shop/guinevere-small-round-sander-p-212.html
With all these you can make nice bowls that nobody will think that you can do on a scroll saw.