I think Sea Planes would be a great way to resupply P.T.'s operating independently of Task Force defense. In that way PBY's and similar Aircraft could perform the same function as the C-47 or the M-3 for the land based counterparts. In light of this the down side would be that P.T.'s often do not see the same level of action that their Land Based counterparts do since they are restricted to which bases they can attack (ports, CV's, and Airfield in close proximity to large bodies of water.). Yes, the Storch does serve as a very good Scouting Platform, but the range is far more limited, and with Sea planes you could run more sorties. The biggest drawback is that these planes like the C-47 are slow and cumbersome in terms of being able to match land and carrier based fighters, and most were often very lightly armed in terms of defensive/offensive armament.
The list would include:
United States/Britain
PB2Y "Conrado"
PB4Y "Privateer"
OS2U "kingfisher" (operated from launch catapults from Cruisers and Battle ships such as BB55 the USS North Carolina)
Martin PBM-3/5 "Mariner"
Grumman G21 "Goose"
Fairey "Sea fox"
Germany:
Bv222 Wiking (viking)
Do22 "float Plane"
Do24
He115
Ar196 (single engine, single seat float plane)
Japan:
Aichi E13 "Jake"
Aichi E16A "Paul"
Aichi M6A "Seiran"
Kwanishi H6K "Mavis"
Kwanishi H8K "Emily"
While this list is by no means extensive, all of them were combat operational. The E13 and E16A, Ar196, OS2U "kingfisher" and the Fairey model are the most mentioned single engine float planes that i could find. The rest are Behemoths, to use the word liberally, and could be regulated to the roles I mentioned above. Being said, The Flying Boats probably would not make interesting additions to the game beyond the resupply/scout role and likely would be even more underused than the P.T.'s themselves. Still it would be an interesting sight to see in Game.