I believe the differences between ICR and INR were discussed in pretty good detail in The 26650 Batteries thread. If I remember correctly, the INR are a safer chemistry which is why I went with INR. I know you don't want to mix the types in a multi-cell light!
How about the Sysmax/Nitecore Intellicharger v2? See this comment on charging currents and the way it splits between channels. It won't be fast at 750mA, but you could charge (2) 26650's at the same time. Note that the raised-top's probably won't fit (too long) according to HKJ's comment on button top 26650's possibly being too long.
-Garry