Sorry if this is a repeat, but somehow a lot of my questions do not make it to the board. Anyhow...
Can you paint (latex) over plywood (MDO and plain) after it has been sealed with polyurethene? Do you have to sand the surface down to bare wood? In that case, MDO would not work...
I'd rough up the surface so the paint will have something to adhere to, but it should be OK. If the poly is well-cured, there's no chemical reason why it wouldn't work AFAIK (though I'm no chemist...)
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