I believe this is the one that I have on the retractable carry handle of my Tumi Tegra international carry on:
It is very comfortable to hold, yet slim enough that it doesn't interfere with the retractable handle at all. It is adjustable well. I have to admit the literally opposite criterion from you: I bought it because it is completely black, is barely noticeable and looks like it was part of the case. However, I think they make a "stupidly bright" one as well.