Do you think you could get two frames, no wheels, on one pair of those? Depth is 30 cm isn't it?
I reckon your problem will be the handlebars. There are 48cm bars on the tandem and there's space to fit another frame on there if you did them top to tail.
@Chalfie started
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Do you think you could get two frames, no wheels, on one pair of those?
Depth is 30 cm isn't it?