I mentioned and dismissed the T34/C-97J option upthread. The earliest this is available is 54/55, by which time you might as well go for a RC-97J for the reconnaissance mission as it has substantially more internal volume available for equipment and operators. By the time a T34-B-29 comes to fruition for the crews' sake I hope it is in a stand-off role! Hmmm... USN GAM-63 Rascal toting B-29s for Sverdlov plinking?
Oh and in my defence, I only mentioned T40 as a way to get a B-29 turboprop variant in a timeframe that the B-29 is still something like a viable combat aircraft not because I thought it was a good idea!
Couple of other bad ideas that I may end up building:
A mixed wing of B-50s with a few knackered B-29s to bolster the numbers (B-29s used for training/as hacks etc) are forward deployed in Turkey when the Jupiter MRBM suffers a spate of pad explosions and is delayed, as a fig leaf deterrent. Then when Jupiter is finally deployed, rather than waste fuel bringing the B-29s back, they are gifted to Turkey (minus their more potent warloads of course). To compensate, Greece gets some RB-45s that were keeping an eye on the Aegean and Bulgaria re-converted back to the bomber role to maintain a semblance of balance.
Bell get a contract from Marquardt to test some of their ramjet designs so use modified surplus X-1s dropped from B-29s - essentially an unmanned X-1 with a conical-centrebody (MiG-21) nose intake and external booster rockets to get them up to speed. Ramjet development continues to the point we get baby Navahoes under B-29s....