Show error on top of cart (/order) page (any page?)

[Juergen E.]

Is it possible to show an errormessage on the top of the cart?
I can not find anything like this.

Do you know if there are any plans integrating something like that?
I'm thinking of 2 different possible ways.

# use an hook on content-head to show the message. (I've implemented this one for testing purpose)
** Added HOOK_CONTENT_HEAD in template header.tpl on end of file.
** Added HOOK_CONTENT_HEAD to smarty assign at frontController::displayHeader();
** inserted contentHead in hook table
** created method hookContentHead() in my module.
# add an errormessage to a cookie or session field which will show on any page.