After watching "outofaclearbluesky"'s videos on YouTube, I saw his effort at making a top bar frame using dowel rods.
That got me to thinking about trying my hand at a top bar frame. As I was looking over a couple follower boards I cut out, I got the idea to draw a line 3/4" all the way around from the outside edge and cut out the center of the board from that line. This left me with a frame that fit pretty much exactly into the hive with a 3/4" thickness all around. I attached these to some top bars and hope to get some use from them in the spring. I made about ten of these so far.
I'll post again then to say if they work out or not.