Josh, version 1.73 has caused copy & paste to stop working in TinyMCE.
I am using the latest trunk, 19998, and WP MultiSite.
Highlighted text cannot be pasted into a post. At first I thought it was the WP changes to TinyMCE, but I deactivated Ultimate TinyMCE and copy & paste started working again.
It has something to do with copying any text with an image in it. The image seems to break it. An individual image cannot be copied and pasted.