Here's a crazy idea for folks looking for get a more "road-like" head tube angle out of their mtbs. It works best with sloping top tube frames but you can do it with level top tubes as well.
Basically you take a suspension fork and remove the guts from it and compress it all the way. this creates a fork that is shorter than your standard fork, which creates a sharper effective top tube angle. it also will shorten the wheel base a tiny bit and also increase the seat tube angle.. all characteristics of road bikes. With a sloping top tube bike, you can almost make the top tube level.
I haven't tried this out on my drop bar conversion bikes, but i have done it on my polo bike and it definitely changes the way it rides. I haven't figured out a way to keep the fork compressed without using zip ties, but once i figure out a clean way to do it, i'd like to experiment a bit and see how it feels