I've found I2C to be very useful and not that hard to use, once you untangle the interface...
I'm using the NXP PCA9622 LED driver chip, and on page 20 of their data sheet, they show 10k pull-ups on the I2C bus. But you are right - there are many other variables to be considered when driving a SERIOUS I2C bus. Mine is only about 6" long - or less. Just using it to save pins for my LEDs and for the AdaFruit 7-Segement display.
=A.