The speaker you saw that had a midhorn on top was a seven π cornerhorn. It has a bass unit with a midhorn and tweeter on top of it.

If you are interested, you can make an eight π loudspeaker, which uses the same midwoofer as your two π speakers. You'll need a different tweeter and crossover, and of course you'll need to make a different cabinet. But that might be an attractive upgrade path for you.