Scott Pedersen (BatHead) has some really interesting information on his web pages.
One of my pet what-if ideas for the B-29 Superfortress would be to try and make a maritime patrol aircraft out of it.
Basically just put it in markings and paint scheme for a late war or early cold war VPB(H) squadron or similar Commonwealth/UK Coastal Command patrol maritime patrol aircraft. Nothing extravagant aside from markings along with some additional antennas and blisters peculiar to an aircraft of that time frame. A good example of such would be the blisters, bumps, and antennas found on the PB4Y Privateer that could be used with a what-if Boeing P2B-1 (B-29) Superfortress/Washington B.1.
Some aftermarket items are available from
Belcher Bits. Key among these resin bits are the
Leigh Light for the Coastal Command Liberator GRV (B-24D) which should fit without issue to the outer wing. The other item is much more attractive as it is the first generation
Mk24 ASW homing torpedoes. Belcher Bits also offers some
1500 pound mine shapes and 250 pound depth bombs that include different tail options for the mines. There are several other bomb types available from Belcher Bits that might work with the Superfortress but that is up to your own imagination and financial resources.
I suppose ASR/SAR mission equipment should also be considered for the Superfortress maritime patrol/ASW aircraft. Paragon offerd a very nice SB-29 conversion that included the Higgins' Airborne Lifeboat that would look splendid on the B-29 but now long OOP and scarce in addition to quite expensive. In 1:72nd scale you can find this same lifeboat included in the Hasegawa SB-17G/H kit and it is quite detailed in addition to being affordable.
My own interpretatioun of an airborne lifeboat would be to create some kind of containerized liferaft that could be placed between the inboard engines and fuselage so as to keep the bomb bays open for other mission stores and fuel tanks. I have had the benefit of being able to scavenge several ferry tanks from the 1:48th scale AMT-Ertl/Italeri A-20 Havoc kits that has a unique shape. While there is only one ferry tank per A-20 kit you can acquire these things from other modelers thanks to their reluctance to use that part on their own A-20 model. So I ended up with enough to make several paired up halves to create a pod that could easily become a large liferaft that could then be mounted on a bomb rack/pylon between the inboard engines and fuselage on the Superfortress. The large bomb rack can be sourced from the 1:48th scale B-17F kit that included a pair of these things with what appear to be 1000 pound general purpose bombs. A lot of modelers do not use these parts in their build so there is a spare parts box near you with a set of these things just waiting for you to ask for the things :)
Other ideas that have bounced around my head include mounting the four-gun turret normally mounted top-forward to be instead mounted bottom-forward to allow the Superfortress to strafe a surface target such as a small boat or surfaced submarine.
Anyway, those ideas needed to be shared in order to give inspiration to others that are keen to do something different with a B-29.