I have a 14 peninsula, 25 lagoon, and 40 mini from Innovative Marine. I love the tanks. I'm using 3 Kessil A80's over the 25 lagoon, 1 AI Prime over the 14 peninsula, and 1 AI Prime and 2 T5 bulbs over the 40 mini.
The 20 peninsula has a lighting requirement of 26.2" long, 11.8" wide and 13" deep.
With wanting nicer lights, and something that could support a full mixed reef (at 13" deep) I would suggest 2 Kessil A80's. It will keep too much light from spilling, still be streamlined, create good zones for a mixed reef (Even allow for SPS where the two lights overlap).
The only difficult problem with this would be finding a proper way to mount the lights. Some good DIY options out there.
Budget would come in around $260 for the two lights together, an extra $100 if you want the light controller, and then finding a mounting option.