Brian,
I hope John can contradict me on this one, but my investigation into this a few weeks ago brought the following conclusions:
* There is not a Civil 3D 2007 OE for LT (and apparently hasn't been since C3D'04, though that doesn't correlate to my often-faulty memory). (Note: This fits with the fact that I only see an OE for Civil Design in John's link, not for Civil 3D.)
* There is apparently no intention by Autodesk to create an OE for C3D'07. (Still confirming this...)
* There are sometimes issues with the "Export to ACAD'04" process that was meant to get around this (I have a workaround from Autodesk Case Support in my Inbox that I haven't got around to confirming yet).
FWIW, there has been a bit of a discussion in the LT DG about this that you may interested to read: http://discussion.autodesk.com/thread.jspa?messageID=5368263�. I also started a thread about it in there a couple of months ago, but I can't find it now.
Of course, I'm hoping that someone can step up and tell me I'm completely wrong. Anyone? Please?
Trevor