Yes there is a bit of storage space under the seat. I put an 8" Beckson sealed deck plate in the top for access; I store TP and paper towels in zip-lock bags, works great. In the winter I leave open for ventilation.
Not only storage, but better access for pulling wiring or plumbing if need be. Access is the holy grail of boat maintainance/improvement. A deck plate is a great idea, typical of what you get on this site. I will now be adding that to my project list.
You should get the annual brevity and wisdom award for those well-chosen words, if we had such an award!
"Access is the holy grail of boat maintainance/improvement."