I recently became concerned with this same issue. I added a vertical section of 1/2" MDF, in line with the rear walls of the front storage area. This gave me a center support for the bed, and also separated the under bed storage from the front storage compartment. It also may slow someone down trying to get into your trailer by coming in through a front storage door. The foot of the bed sits over the vertical area making up the under bed storage, so it seems well supported. I'm considering adding a few vertical 2x4's to support the head of the bed, however so far it seems sturdy. Despite their **INCREDIBLE** (Cough Cough) quality control, one of the support twigs has an eye in it, and was split almost its entire length. I added a 2x4 next to it to beef it up.
2016 Jayflight 28BHBE Fiberglass/Elite
2014 F-150 4x4 Supercrew, Eco-Boost, Max Tow