I am sorry to hijack this thread, as you mention not wanting to use the services:
with the app “service scrubber” you can assign different/new keyboard shortcuts to services and/or clean out that darn service menu which can get overcrowded very easily.
An alternative solution could be to just use quicksilver to save text to a file which is in a watch folder for DTP, i.e. a folder either with a folder action script, or just one that gets indexed by DTP.
Still another alternative might be to use Leopard’s Mail, or special apple script that does what you want.
It probably all depends on whether you want DTP to add it immediately or just whenever you want to open DTP?