I think you would be better off just removing
notify-send from the equation, given your stated requirements they do not provide any additional flexibility of functionality.
If you are looking for a minimal status bar, conky has a comprehensive amount of functionality, all of which can be updated in real time (depending upon how resource intensive you are prepared to accept it being).
If you wanted to tailor something specific to your setup, you could also use simple scripting and dzen.
You could also combine the two and pipe conky to dzen for your status bar; which also means that you can display icons in the bar, if that is what you are after.
There is a long conky thread on the Arch boards that has a myriad of different configurations and approaches to provide some inspiration.
For simple notifications, you could combine
inotifywait (from the inotify-tools package) to achieve this. For example, I use this script to notify me when my nick is highlighted in IRC:
while inotifywait -qqre attrib "$dir" >/dev/null 2>&1; do
echo "IRC:" "You have been pinged..." | dzen2 -p 5