i have been looking for one of these also. egt gauge would work but the response time is very slow. there is a certain type of thermocouple that they use for them, i think type k but not positive. i have talked to lazarsmith and he said they sell one but havent heard back from him yet so cant offer much info about it.
I talked to autometer and they said they didn't sell well so the discontinued them and don't plan on making them any more. The nordskag will work although I don't like the style but that and they only go to 300* and I'm pretty sure the air on the hot side of the IC is warmer than that. Also the EGT gauges don't go low enough as I plan to use an A/W cooler between stages and if using ice from time to time it's possible to run cooler than 100*