Yes, this is an important requirement for me. I'm daisy-chaining Netduinos through serial ports, and propagating serial data frames across the chain. If a netduino ever looses a piece of data, it will be desynchronized with no ability to easily find the start of frame again. One solution is to send a short break at the beginning of each frame, which will force every netduino in the chain back into a known state, whether they are in or out of sync.
The short break provided by the SBK is enough for my needs,but I reckon there might be other needs.
Yes, I'm comfortable hacking the firmware (with proper guidance). It's either that or do ugly things in my code for sync purposes, so if push comes to shove...