Many applications place an icon on the notification bar. But then to get to the action I need to long tap the notification bar (taking care not to tap the screen area below it) and then pull it down (at least this is how i do it in my htc desire hd)
Is there an easier way? Maybe assign this to a long press on the menu button (same as long press on the home button shows recent apps)?
To answer your questions, yes - there is an app that will allow you to invoke the notification panel:
exsbar allows you to assign the long-press search button or long-press camera button to this function.
Whether or not this is "an easier way" depends on you, the end-user. :-)
You shouldn't need to long tap the notification bar, just tap and swipe down.
You can also press the Menu button and then "Notifications" to pull down the notification screen. It will not be shorter but you will not risk pressing the shortcuts on the top of the screen.
And on some phone when holding it with one hand it is easier to use the Menu button than to reach the top of the screen.
