The Janome 3160 is also 12 pounds and has the thread cutter and needle up/down that I have on my 7700. I have had both the Jem Gold and Jem Platinum as well -- I like the 3160 better but it is a bit more pricey. The 3160 has been discontinued, but you may be able to find it. I believe the Jems have also been discontinued.
Are you sure the price of $50 was for the walking foot alone or for the quilting kit (1/4" foot, walking foot, darning foot and the darning plate)? The kit runs between $50 and $60 on line.