I was wondering if you could talk more about this. When I wanted to do my mountain bike to drop bar conversion I ended up buying a smaller mountain bike frame (1995 Trek 820) for a shorter top tube length. I felt that if I tried this conversion on one of my ideally sized mtb's I'd be too stretched out. Anyway I used a Nitto MT-10 dirt drop stem with 100 mm. I used the longer stem because since it angles up more that horizontally and I wanted height that I needed since the frame was smaller. Anyway, who knows. This smaller size may not work in the long haul. It feels great now though.

To the OP - if you've got the stuff laying around why not try it and report back. Sometimes things look good on paper, but not so much in real life.