If they were my humidors, I would remove the lid from one and make that the bottom. Then, I'd zing the bottom off the other on my table saw, to make that the new top. Assuming they were both made to the same specs, they should glue together with not much of a seam showing.
I'd be more comfortable having a go at it if they were mine, but would be happy to make the mods for the OP. PM if I can be of any assistance.
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