Well, I just shot my ebayload on a rather nice looking Bernina 540 'Favorit'. I'll pick it up on Tuesday, it'll be interesting to see if the bobbin parts are the same as my 117 as you suggest they might be Mickey. Here it is.
I love the '50's styling, -even that 'orrible snot-green colour is cool in this context!
I'm hoping it doesn't have any stripped plastic gears... I would have thought this era would have had all steel gears, but I don't really know. Fingers crossed.