WC8, WC32 I2C bus

This is a question initially directed to CAI, but anyone who can answer, please do!
 
Firstly, what speed(s) does the I2C interface run at on the WC8 and WC32.
If it can operate at multiple speeds, what is the speed selection mechanism, and can the user determine or control it?
 
Next, what is the maximum supported bus length? I know that will depend on the cable characteristics, but I've had no end of problems with systems using I2C with cables even under 3' long. Worse, while they initially work, they seem to crash, lock up and/or require resets anything from a few hours to a few days, perhaps a week... whereas without the I2C they seem to run many many months without attention.
 
Finally, has anyone used I2C bus extenders, what did you use, what'd they cost, where'd you get 'em and how happy are you with them?
I've been considering building some boards and using either the P82B715 (which claims it'll driver 3000pf and up to 50m of twisted pair), or P82B96 (which claims over 100m). I don't have a need or desire to drive 100m, but certainly 20-30m would be good.
 
IF there isn't a device out there now for a "reasonable" price, is anyone interested in some if I were to make 'em?

I2C bus speed has 100kbits/s mode, that is what we designed for. Since I2C timing can be for as long as possible, it can operate slower than 100 kbits/s speed.
 
The I2C bus is depending on line voltage change to communicate, so that any electrical noise can cause line level change can cause problem.  One way to find out is to attach device next to the board. If that can operate correctly, then most likely the problem is caused by noise.  In that case, add bus extender could help a lot.
 
With so many I2C sensors out there, it can greatly extend the possibilities of WC IO functions.  We do want to see the best way to support better use the I2C bus.