What you talking about is in ■ Applications → Utilities → DigitalColor Meter ■
You might like QuickPicker better, though. I was actually just searching earlier for a widget that could offer an eyedropper function, but the best hex program I found was QuickPicker. QuickPicker copies a code like this: #000000. Apple's DigitalColor Meter records "#000000"
with quotation marks too, which just doesn't work very well with Adobe's Creative Suite or many other programs.. so I'm not sure why it's made like that and can't be customized.
I did find a dashboard widget called Colourmod, which is a decent color picker (not eyedropper). Still, I know it will never be nearly as useful to me as Screenshot plus, the Kuler widget, and Pandora, which is the best ever use of a Webclip.
I know it's more than you asked for, but I thought I'd name some things that could be useful to you too.