I want to piggy-back on this thread, with apologies to the OP. It sounds like you Shimano drivetrain gurus are saying something that will help with my current question/problem.
Can I use any modern Shimano 8, 9, or 10 speed road or mountain derailleur (like the one suggested above, for example) with a Dura Ace 10 speed indexed bar end shifter and 10 speed Shimano/SRAM cassette?
I know there are tons of websites that lay out the cross-compatibility or lack thereof for almost any combination a guy would want to try, but they have so much information it can be hard to pick through and find an answer on my particular setup.