I had some spare time today, a really nasty plugin I had written for jQuery a while back to do character count downs and a desire to play with the widget factory. Let's get it on!
First things first, I have give thanks to Adam J. Sontag for showing me the way with the widget factory. I had tried it before but was missing something (namely, the scope of this in event handlers was eluding me). Then I saw an example in Adam's slides.
$.proxy! So that's what that does. He caused my eureka moment, and for that I am grateful (just missed Thanksgivings by a few days, sorry Adam).
Basically on a litany of events it counts the characters in a form field and compares it to the specified max (either a config property or maxlength value). It can do the threshold coloring like twitter does. Actually, it was modeled a lot after twitter.
You can check it out at the GLGUI Toolbox and there is even an example page.