I have working firmware for a few SiLabs ESCs for BRUSHED. Yes I did say brushed operation. Might be a useful starting point for reading in RC pulses and getting outputs up and running. I haven't mapped the ADC inputs but most of the other stuff is done it should mostly be contained in Header Files.
Have Plush10, Plush30, HK10 working atm. I am also working on a few which contain the F310 micro. These seem to be the higher end ones.
Check out http://robowars.org/forum/viewtopic.php?t=1581
(long thread warning)
I am much more active on Robowars forums than here so if ping me there if you don't hear from me and want more info. I am interested in doing brushless dev but have never really had the time to do it.