Dura-Ace 9 speed downtube shifters compatible with mountain bike rear derailleur?
For various irrational but otherwise perfectly valid reasons I'd like to use Dura-Ace 9 speed downtube indexing shift levers and a 32 or 34 tooth maximum cog. As far as I can tell those cogs require a "mountain bike" derailleur. The spec sheets for Shimano's mountain bike derailleurs usually say something like "Compatible with all mountain bike shifters" so I'm not convinced the DT shifters will work with the off-road derailleurs.
Anybody know the facts?