this may be a ripe category for a freeware/donationware alternative.. maybe harrie can tell us about what a perfect tool for this would look like, and try to think if there are any features that are missing in these tools that would be nice to have.
-mouser
It will be good if you will have time to code this up. I have been looking at these types of applications before, only IntelliComplete is the best.
Speed typing are split into three categories - text expander, text correction, and text completion.
Text Expander - Many programs of these types around. Idea is using a id to expand into a full sentence. e.g type "fyi" will expand to "For Your Information"
Text Correction. One example is AsUType
http://www.asutype.com/. It corrects the word while you type. Useful but not as useful as text completion.
Text Completion - This is where IntelliComplete is different from other programs. It predicts the text based on dictionary. Example, you type 'he', then it will present 'hell', hello', helicopter' etc. It also offers text expander.
The only problem with IntelliComplete it has a threading bug which causes it to stop working after a few hours and it's caret detection doesn't work well with all programs.
The similar programs I have seen are
http://www.clasohm.com/lmt/en/http://www.wamasoft.com/autotyping/However, their speed and memory usage are not as good IntelliComplete, though they don't suffer from the same bugs.
If you can replicate IntelliComplete without the bugs, it will be excellent. For your information, they have their autocomplete editor at
http://www.flashpeak.com/inted/inted.htm