tcmtech, that's where things get a bit sketchy, because much of the change in modern NiMh's has come from drastic changes in internal structure and the materials it's made out of as they've gotten better over the years, the cell chemistry itself isn't much changed just how it's put together physically.
It's like a marine lead acid vs a starter battery lead acid, the chemistry is the same (more or less) the biggest change is in the plate shape and layout where marine batteries go for thicker plates with low surface area for durability and starter batteries maximize current draw my using meshed plates to provide a lot more surface area.
I'd skip NiMh altogether and jump right on the Lithium battery bandwagon if you can.