you can use any short, mid arm, or long arm up to 18 inches.
short arms include
juki 2000, 2010, or the older 98 models
http://www.sewvacdirect.com/jukisew.html
janome 1600 series
http://www.sewvacdirect.com/janomehi...gmachines.html
brother 1500 series
http://www.sewvacdirect.com/janomehi...gmachines.html
mid arms and long arms - include Bailey, Handi Quilter, gammill, etc
http://www.baileyssewingcenter.com/homequilter.html
http://www.handiquilter.com/
if you buy a machine thru Sew Vac Direct i would totally call them first and ask if they can do some sort of package deal with the frame and machine.