This AppleScript will append text to the title of the selected notes in Evernote.

EvernoteTitleAppend.applescript

tell application "System Events"
  
	set the_dialog to display dialog "What would you like to append to the selected notes?" default answer ""
	
	set append_text to text returned of the_dialog
	
end tell

tell application "Evernote"
	
	set theNotes to get selection
	
	repeat with n in theNotes
		
		set theTitle to title of n
		set title of n to theTitle & " " & append_text
		
	end repeat
end tell