I installed StrokeIt and configured it the way I want. No triple-click (obviously) but now I've got a gesture that does what I need. Thanks!
Programmy my middle button to do something would be great, but this particular mouse (el cheapo Dell) has a hard time discerning between middle-click and a scroll. Sometimes I get both, sometimes neither. So alas, I must stay away from my middle button. Which kind of sounds naughty but rest assured, it's not.
I'd still like a triple-click thingie, but I can live without it. I recognize it's a hard thing to detect and also many applications (MS Word) use triple-click to mean "select a whole phrase" so it'd be fun fighting that. In my case, I only need it available in one app, and it ain't Word. :-)
Thanks again for the awesome lead -- I wouldn't have found StrokeIt on my own. Which, again, sounds naughty but it's not...