I think the extra wide feed dogs on embroidery-enabled machines may make getting an accurate scant 1/4" seam more problematic. Aside from being so wide, the feed dogs are also designed to accommodate multi-directional feeding. One reason vintage featherweights do such a nice piecing seam is because the feed dogs are quite narrow; another reason is because the feed dogs are designed to feed fabric in only two directions (forward and back).
Several people have mentioned the Pfaff Passport 2.0 as being a wonderful lightweight machine. I believe some of the lighter-weight Janomes also have the features you are looking for. The advantage of the Pfaff is the IDT. If I can find them, I will link one or two recent threads about these types of machines.
Edit: Okay, here's one thread:
http://www.quiltingboard.com/main-f1...s-t241649.html
and here's another:
http://www.quiltingboard.com/main-f1...s-t238748.html