I'm considering going to layer 3 to my IDF's. How would this work? If I buy 4 switches with the SMI image and 1 with the EMI do they sync IOS version to the EMI or will only 1 switch have the expanded IP capabilities?
The switch cluster has the capabilities of the master switch. Let's say the master switch has EMI and you configure it with some EMI features. It then fails and an SMI switch becomes master, all those features are not supported and removed. That will cause more trouble than what it's worth to buy the correct image for all the switches.
Hope that helps.