Nope. It's not customizable, you just get the notification (email, whatever) and the time. When the battery is really low that shows too.
There have been a lot of suggestions/requests in the G+ communities to add more information to it but I honestly like the simplicity of it. If I need more info then I turn the display on.
I would like to be able to go to a specific notification/app if there are multiples showing and I would like it to clear them (out of the notification bar) if I swipe them away. Other than that though I like it just the way it is.