First, I created a dart for the LMKG bonnet and it now fits so much better - more snug around the neck. I've noticed comments on ravelry about this design aspect too, so I know that I'm not the only one; and I didn't knit it up wrong. Here's a photo of the new back. I basically sewed a seam and then tacked down the excess along one side.
Secondly, for the gift bonnet I branched out on my own and modified the LMKG pattern to create a bonnet that fit more snugly. I am really, really happy with this modification. This bonnet is already out the door, and from what I hear the mother-to-be loved it. If anyone is interested I'd be happy to write down my modifications and post them here. It creates a bonnet that fits the head a bit better - more form fitting. Here's a photo of my "model" wearing the hat.
Lastly, here is a photo of my same model in the gift bonnet from Lily. After some queries on ravelry, it turns out this is likely a bonnet pattern from EZ's The Opinionated Knitter. From my responses it seems the general shape and construction are hallmarks of EZ's designs, but the colorwork appears to be an original addition. I don't have a copy of this book yet, but it's on the Christmas list. I can't wait to see if I can re-create something similar!