There are two ways that I can think of:
One involves running an apple script and mapping keys, which is difficult depending on your skill level, it is described in this post:
http://macscripter.net/viewtopic.php?id=19711
The script requires that you have support for assistive services enabled, which I had to do. This can be found at: /Applications/System Preferences/Accessibility/
I've extracted the script here.
All you need to do is save the three files changing one line:
activate application "TextEdit"
tell application "System Events" to tell text area 1 of scroll area 1 of window 1 of process "TextEdit" to if exists then
set {x, y} to value of attribute "AXSelectedTextRange"
if x ≤ y then tell application "TextEdit" to set color of document 1's characters x thru y to {0, 0, 0}
end if
All you need to do is copy the above text and then save it as a file called "black (or whatever you want).scpt"
For changes to Blue you need to change the second to last line to:
{0, 0, 65535}
For Red; and
{65535, 0, 0}
For Black just use the one I posted above.
Then you will need to assign the AppleScript files to a keyboard shortcut via Automator, although there are third party tools that make this easy.
The other uses the shortcut: Command + shift + T and having the three colours already defined in the boxes below. I assume you are already doing this? And it does not really qualify as keyboard shortcuts.
Best Answer
According to @IconDaemon there is no key combination to do this. A possible workaround is to select a word or phrase, or line that you want to move and while holding the mouse button down you can drag the selection elsewhere in the file.