Engine house for a 2-8-2

For a Mike you want something a little more substantial:

Like this one from Walthers:
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Or this one from Vollmer:
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This one from Campbell:
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Or this one from Heljan:
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I think you're going to have trouble finding a wood structure the size you want - they tend to be built for smaller locos... switchers and narrow-gauge and such.
Of course there's nothing stopping you from starting with a kit you like and adding to it... ;)