Was a B-29-sized aircraft carrier ever suggested?

Did anyone suggest building an aircraft carrier large enough for B-29s to operate from it?

The idea appears to have been suggested, but he does not think such a carrier was built.

A carrier of this kind appears to have been suggested, although the answer is tentative and no completed ship is identified. No design name, dimensions, or programme history are given. The idea was discussed, but the answer does not establish that an operational B-29 carrier came close to construction. Its value is as a limited lead rather than a complete design history.