People who type a lot are likely to be working with some level of jargon (variable names for programmers, macros and cell codes for data analysts, etc.) rather than the pure prose autocorrect is designed for.
AFAIK, there aren't any good demos of autocorrecting keyboards for technical domains. That said, TextMate's autocomplete works pretty well most of the time. If you could seed the autospell dictionary with a combination of language-specific keywords and the variables that have already been defined in your project (ala TextMate), that could be pretty powerful for technical people trying to be productive with alternate input methods.
As an aside, “Using Python to code by voice”[0] is quite an inspiring presentation on the topic.
Also, I am not sure how this thing makes anything better: you still have to do hand movements correctly and most people will need some kind of surface to orient their hands on. Same problem, without a keyboard.