Looking for something else, I stubled over some interesting information.
"SMBus and IIC is the same" has been stated many times, however as seen below there are differences.

http://forums.semiconductors.philips.com/acrobat/a...0216_1.pdf
starting at end of page 31 has a detailed comparison between IIC and SMB.

Now, here is the funny part: I have found many parts with "SMB" that really are IIC (no timeout etc).

So, I regret to say, you need to dig into the datasheet for SMB devices to see if it is a SMBus device or an IIC device that has been named SMB to avoid Philips rules.

Erik