Your going to want to search up 3t quill stems on ebay. They made some of the lightest, nicest looking ones up through the 90's. I bought an NOS one for my girlfriend's De Rosa not too long ago at a really good price.

Also, around the time they went from quill to threadless i know there was some experimentation with making lighter/easily adjustable quill stems. I would ask over at C/V about them.

Something like this for example: http://www.ebay.com/itm/3T-1-quill-s...item3cbe594e4d