Reactive Keyboard enhancements?

[http://dummy.us.eu.org/robert (robert)]

Hi.  I e-mailed you a while ago, but you never responded.  Maybe I'll have
better luck this time.

I would like to enhance the reactive keyboard.  Namely, I'd like to make
old sequences "decay" with age, instead of using only pure frequency; i.e.,
later sequences should take higher precedence than earlier ones.  I was
wondering if anyone else has tried to add such an enhancement.  (I do understand
that occassionally the frequencies get halfed and that probably helps, but
that doesn't seem quite sufficient.)

Thanks.