i would get a 20U clone and attatch a roller foot. It will do the job even at 138 thread. it also has zigzag. simply replace the feet between functions.
TWO MACHINES IN ONE !?!?!?!?!? thats right folks.
I got mine with guts feathers and all delivered for under $700.
google: Zamir sewing
he's a good man and can get anything you want.