Catherine,
You might take a look at Curtlo too. Similar to Gunnar in that they offer quality steel frames for less.
Crankin and company have touched on what I was trying to get at in my previous posts--although not very artfully. You're right that the Coda is lighter than your LHT, but it's still heavy by road bike standards. Heck, the 2011 Coda is just a pound lighter than my 2010 Jamis Aurora. I'm afraid that if you go the Coda route, you'll eventually kick yourself for not going with a lighter bike.
That said, it's helpful to remember that the frame is just one element of weight. Even if you go with a Gunnar frame, it's not going to be particularly light if you build it up with heavy parts. So, keep that in mind as you decide what to do. I would also note that you may not need mountain gearing if you end up getting a lighter bike. You could potentially get away with generous road gearing. That'll help with weight and give you much more closely spaced gears--which I personally like on central Indiana's mostly flat roads. It's much easier to find that perfect gear.
Having road bike shopping!
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher