I have a new Pinnacle 31 RLTS that is on order with a March 1 delivery date. I last looked at one on the dealer lot in mid October, so hope my memory is correct. I can not give you the exact dimensions of the basement storage area. It seemed to compare similarly in size of our current 28.5 Eagle SuperLite's. However, the street side of the basement storage is narrower than the curb side because space is occupied by the Uni-dock Utility Center. Since there is only the DW and myself, the lack of full width access to basement storage from the street side was not a deal breaker.
We really like the floor plan and size of the 31. We are anxiously awaiting the arrival of spring to get our new "baby" and start the shakedown process.
Good luck with your decision.
'06 2500 Silverado 4X4, Duramax LBZ Diesel, Firestone air bags
'08 Tracker Pro Guide V-16 Boat
'12 Pinnacle 31RLTS