I would like to point out a slightly different point (sorry if it is obvious, perhaps...):
1st, I do not think that the pure typing speed is sooo terribly a difference (unless you are speaking of someone that codes one character per second or every 4 seconds!!!):
I always thought (and seen based on evidence from some projects) that in the medium-long term (in the 4 or 6 month of a project, I mean!) the big difference is made by the overall quality of code...
perhaps, I repeat, that's obvious, but I think that a set of well made C++ classes, right architected, is more important than typing fast
(I admit that being all the other points the same, then typing speed brings some difference, though...)
ANYWAY... the thing that I wanted to say first, was another one:
I think that , MORE THAN BEING FAST AT TYPING, one more important thing (or, I dont know if actually you considered this also one aspect of speed typing!) is to be really proficient with your tools:
I saw once a colleague of mine (that, btw, I respect a lot for his qualities as a designer generally speaking: he is brilliant, deep, good skilled and also really a nice guy to work with) that also was absolutely proficient in the usage of the EMACS editor:
this, I think, is a slightly more important difference than being fast at typing: he was actually really able to do all the imaginable things at an extremely high speed from inside of EMACS, and this for sure makes some difference in the amount of code that you are able to produce, compile, test and debug in the 8 (ehr... 10 or 12) working hours that you have available in a day!
p.s. sorry for the bad english!!