You could make it from a pair of tubes - make the curved section then mitre it to a straight section of seat tube. If you have the seatstays joining where they are in the above pic it should take the stress.
@O'Shane started
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You could make it from a pair of tubes - make the curved section then mitre it to a straight section of seat tube. If you have the seatstays joining where they are in the above pic it should take the stress.