Hopping foot for Pfaff Expression 2.0?
 

I have a Pfaff Expression 2.0 and use it on my handiquilter frame for free motion quilting. I would like to do some ruler quilting, example crosshatching and scallop work, on some of my quilts. I have both fmq feet for my machine, but they are not completely round. My question is: Does anyone know if there is a round quilt foot that will fit my machine, like the Hopping foot for long arm machines? I really would appreciate any help you can give me.

You will need to use a long arm ruler, not a rotary cutting ruler. These are at least 1/4" thick so in addition to it being round, the part that attaches the round bottom needs to be high enough so that your ruler will fit. Probably not making myself too clear...
Couldn't find an exact photo, but here's an open toed foot that will illustrate:
http://www.sewingmachinesplus.com/tin_foot.php
See how high that shaft is? It needs to be really high to clear the ruler.
The ruler has to be thick so when your foot hops, the ruler can't slip under the foot.

Thank you for your information, I understand about the rulers etc., what I was wondering is there a round fmq foot that will fit my machine? even a generic foot, both of mine are more rectangular and square.

See if there is a round foot with the Pfaff embroidery machine. I don't have any round one with my 4.0.

You can buy hopping feet for pretty much any machine you have. You just need to know what kind of shank you have - high, low, slant. I like http://goldstartool.com (not affiliated, just a happy customer) They ship quickly and for free in the US.
Search for darning foot. If you don't see what you are looking for, call them. They are very nice and will get you exactly what you need :) I just ordered a binding foot from them and will be ordering the binder attachment for my Juki soon...