Here's my thing: Mora knives are great and light, but they don't add a lot of funtionality over a good folder like the A.G. Russell Featherlite because they aren't full tang knives. If you want a fixed blade, I strongly suggest getting one with a full tang, otherwise you sort of cheat yourself out of the benefits of a fixed blade. Yes, the full tang adds a bit of weight, but your blade won't snap off when you need it the most.
Here are a couple suggestions:
or here with a serrated edge:
The knife has a very tactical look, but it has a serrated edge and can easily be mounted upside down on a shoulder strap. If you want to get away from the tactical look, try a handmade Carver knife made here:
and pictured here next to a Mora:
Lastly, what about a no frills neck knife like this:
You could get it wrapped in leather if you don't like the paracord, and you could get Charlie to add a serrated edge.
Both the Carver and the Charlie May knife can be worn around the neck. You might like this better than the pack strap because, even if you take your pack off, you've still got your knife with you.
I'm ne to lightweight backpacking and, up to now, I've always thought that a good knife was very, very importat piece of gear to carry. It can really help to bail you out of a lot of trouble in a pinch, so I don't know if I'll be able to ditch mine to save weight any time soon. Blasphemy here, I know....