I’m in the middle of a quill–>threadless conversion myself. Right now I have a Nitto Pearl quill (110mm) that is just too long and am waiting for the 22.2mm quill–>1 1/8″ threadless adapter to show up in the mail this week (this one: http://www.universalcycles.com/shopping/product_details.php?id=23896 )
Its an old ’78 Schwinn Super le tour, and the headset measurements are all odd (31/32″, really…really?) so I’m crossing my fingers that everything will work.
If it does work, I’ll be more than happy to let you try out the old quill stem, if its something that will fit. Diameter is 22.2mm and reach is 110mm – oh and the clamp size is 26.4 (another odd measurement – fortunately there are quite a few people making 26.4mm bars – Somafab makes the good middle-of-the-road stuff, Nitto has the high-end stuff. Search universalcycles for [26.4]