I think what you really want is rising and falling edge detectors. You're only concerned when the first light detector goes high, and when the first light detector goes low, and not so concerned with the state of the other light detectors. From there, you can wire them into an RS NOR latch.
Since simply wiring all the outputs of the light detectors together is equivalent to ORing them, you'll only need one rising edge detector. Have that feed into the SET input of the latch. You'll also have to feed the output of each detector into their own falling edge detector, and from there wire all of them into the RESET input of the latch.
You'll also have to isolate the outputs of the light detectors from each other leading into the rising edge detector, but that's easily accomplished using a repeater.
UPDATE:
After tooling around in creative, there are some additional things that I noticed. First, I had to use a pulse extender on the reset input to the RS NOR latch (I used the sticky piston version). Secondly, the delays I used for the edge detectors is slightly different than what is in the wiki. As with a lot of redstone circuits where timing is important, it's usually necessary to adjust the delay on the repeaters to get everything to work properly. Finally, if combining the signals from the various light detectors before passing them through the edge detectors, you may notice that a set or reset doesn't toggle the latch. This is very unlikely in a light detector since all of them should change states before any change back.
As promised, here are some MCEdit schematics. They aren't the prettiest, but they're functional.
An item frame is an item, so you can put it in an item frame. However, an item may only be placed in a frame by right-clicking a wall-mounted frame with it, so frames in your inventory are always empty. Thus, you can only place an empty item frame into an item frame.
Best Answer
Turns out the problem was that I am really disorganised. I had my maps all over the place and couldn't wrap my head around it.
I started a new creative world to try from scratch, but this time I organised every map in my inventory in the same formation that it would be on the item frames:
I then created each map one by one, starting with the center, making sure I put it back in the correct position afterwards:
I did this until I had filled out every map:
After I had filled out all of the maps I put them in item frames row by row until I got this final result: