I use a lot of layouts with multiple map frames too. One thing I found that was pretty cool was that you can have irregularly shaped map frames. In one instance I created the main map frame with a a rectangle chunk taken out of the frame and the other frame put in that place. Still doesn't work like neatline but is a cool feature. Its been so long since I was able to use the neatline though that if I had the feature back, I probably wouldn't use it now. My original post was from 5 years ago.
Josh White, AICP
Principal Planner
City of Arkansas City