while i was searching for info on the quantum..i came across this seller on ebay..
http://cgi.ebay.com/14-PCS-LOW-SHANK...-/250783844933
she sells presser feet kits. she has good rating..but i am not sure if the prices are good or not. been a long time since i bought new feet for my janome.
i believe all Jamones are Low Shank except the 6600. not sure about the newest model out the 7700.