I never had anything like that on a pontoon, but it sounds like a good idea, Are you thinking hinged and attached to the rail, so it swings down when not in use, or full blown part of the furniture, with tackle storage, everything in one place?
On the old Tracker I did have dry storage in the corners in the bow, and the tops of the boxes became catch alls, and work areas. They were probably under 2 square feet, I think you'd need a little more.
I like the idea of a work area with a space below to store a bunch of Plano boxes.
Is it portable? Maybe drops in a seat base, so you can take it off the boat? Too much coffee?
2006 Forester 19 Fish (new deck and carpet, Pontoonstuff interior, 2019)
1996 Mercury 50 ELPT4S
1983 Sea Nymph FM171 Striper (complete rebuild from hull up, 2014)
1985 Johnson 70 J70ELCO
Raystown Country, PA