It's all working pretty good so far. We have had acouple issues with the D4's. But, the sound quality of the D4 is amazing. It's sounds just as good as a cable.
Hmmm, what were the issues? Power? Positioning? Transmission range? I'm very curious to hear how these work in the real world.
how can I get an idea of what a good rate is for these 'extras' without stepping on some unwritten rules about posting these things?
That's all part of making the deal. In two recent cases, I dealt with a lowball bid by pointing out the compromises they would run into with sound at that rate. We went back and forth a little bit, and ultimately they leaned more in my favor and it worked out OK. (In one case, I found out I was being paid the same rate as the DP.)
But I've also run into the same thing that Richard Ragon's talked about -- real bottom-feeders who have no clue what good sound is worth. I'd like to kill the morons who write those "Indie Films for Dummies" books who tell neophytes they can get sound crews with gear for $100 a day...

The other misconception are young filmmakers (particularly Red users) who think they can buy a $1200 recorder and a couple of mikes, and that's all they need. No respect for the archer -- they think it's all about the arrows.
--Marc W.